How to make a Lego Cake

I has been wanting to make a lego-type cake for a very long time.  I am not sure why I love Legos so much but I do.  I used to have a Lego school set when I was little and I LOVED it.  Even before getting this cake order I would research how to make a Lego cake.  I always wondered.  But I didn't have much luck finding any tutorials out there.  So we are!

I saw that there is a "cut out a lot of little nubs" approach, where after you cut your rectangle you individually place every little nub on top of it.  Sorry, but this was NOT something I was willing to do.  There was NO way I was going to make hundreds of itty bitty nubs to put on top of Lego pieces and in so many different colors.  Not to mention it wasn't going to look super 'neat'... and that's always a big goal for me, a NEAT looking cake.

I needed a mold.  Something where I would NOT have to cut out little nubs.  Something that looked JUST like the building block pieces.  I searched and searched but could not find a Lego mold that would work ANYWHERE!  I even ordered one that turned out to be the size of big Lego ice cubes! (these are the big yellow and blue ones on Amazon).  So if I wanted to get that perfect Lego-look this meant I had to make a mold myself!

So I did... and now actually make these for anyone who is also up for creating this super fun cake!
Now available on our website here.

Keep in mind this cake is all about the prep work.  If everything is well prepared, putting it together will be the fun part (and everyone will love it!)!  So here we go with the materials and steps to make this super fun Lego cake!

For a cliff note description check out our youtube video:

Decorating Materials

The Mold
Make your own or purchase from our shop here: the single mold, the 6 cavity mold.
To make your own, use a lego piece and silicone (there are a variety available from  Secure block piece on glass with buttercream and with a cookie cutter around it.  Work air bubbles out at each lego 'nub' with a large pin.  Apply buttercream at edge of cookie cutter.  Weigh and mix mold media, pour, let cure for required hours.


Name Topper
Make a 2D name topper with fondant and a font printout / template (available on our website here and included with all mold purchases). Here is our tutorial on how to make a 2D topper (this is a Mickey topper but I use the same techniques). In sum, roll out your fondant to desired thickness, let dry for about 10 minutes, then, using pieces from your cut out template cut out each letter.  With the cut out pieces stick them on the background pieces with shortening. 

Cake Couture Fondant
You will need fondant colored in primary colors:  Red, Yellow, Green, and Blue (but omg just imagine a Friends pink, purple, and white block cake!! Sooo cute:)). You can find our Cake Couture Fondant on our website here or you can make your own marshmallow fondant which has similar properties. Whatever you do, I don't recommend Satin Ice. This is a great fondant for many other purposes, however, for this project this fondant doesn't fill each cavity very well and lacks firmness to make those neat-looking pieces.

In general, our Cake Couture fondant has the right firmness, flexibility and texture to hold molded shapes and creates nice sharp cut outs (make sure you let it dry rolled out for about 10 minutes prior to cutting with a template). It is even better for such purposes when the fondant has sat for a day or two after making it (this increases firmness which is great for molds).

Your cake 
I used a 1/4 sheet cake (9"x13") here to get that extra block-y look :) 

Chocolate Ganache  Your favorite ganache recipe will do, however you can also see gananche instructions on our post here.

The Steps

Step 1. Prepare The Blocks - for a really sharp look prepare 2 days in advance.

  • A couple of days before you want the finished cake make a number of block pieces for the top using the block mold and your different fondant colors.  
  • TIP: Cake Couture Fondant works best. Achieve similar 'firm' fondant by making and coloring your fondant at least 1 day before making these pieces.  If your fondant is sticky try adding a dab of shortening or powdered sugar.
Roll about a 1" ball of fondant (roll it enough to get all of the creases out), then push the ball into the mold cavity real well with your fingers (not a roller). Then using a sharp knife cut off the excess on top so that it is flush with the mold. If this gets to be too sticky sometimes it helps to rub a little extra powdered sugar on top before cutting the excess fondant. Then just bend the mold back with your fingers and pull / peel the fondant piece out of the mold slowly (do not use anything else but your fingers so as not to damage the mold or your piece). Re-square the soft pieces with a knife or spatula on a large flat surface dusted with powdered sugar.  You should be all set!  
  • I recommend starting with the lightest fondant color and working your way to the darkest (I would do yellow, green, red, then blue).  This way you can keep from cross contaminating your fondant colors and save yourself from dry hands due to over washing them. The reason you want to do this well in advance is to allow your pieces to dry create 'sharp' looking blocks.  Drier fondant is sharper looking fondant and sharp looking fondant always looks cleaner and gives a more finished look.  But if you are out of time last minute is OK too!!
  • Next get a rough idea of how many pieces you need per color by estimating how many you will need to cover the top of your cake pan and cake board. (hint: try to envision how much fondant it will take to cover your pan)
  • The size I used is a 1/4 sheet and for the look I wanted it required about:
    • 50 green mold pieces
    • 23 yellow mold pieces
    • 13 blue mold pieces
    • 13 red mold pieces
  • Let the pieces dry for a full day or two (minimum overnight).  You can save time by not fully drying but the pieces will have a softer look to them. Store them on your trays in a cabinet or drawers out of sunlight and bulb light to prevent them from fading or changing color. 
  • Notes on storage: DO NOT store them in an air-tight condition, this will cause fondant to sweat and stay soft, however, if drying out for about a week or so you can do this, however, I would test it.  You might be able to store them in a paper box (anything but air-tight) but the lack of open air might affect integrity.
  • Once they are fully dry cut the block pieces evenly into 3 smaller pieces.  I didn't cut all the green pieces since I wanted to use these for the cake board.
  • The pieces are now ready!

Step 2.  The Name Plate Topper

  • While you blocks are drying, and since you have just worked with all of your colors you can now use this fondant to make the name plate.
  • Using a block font paper template, cut out the pieces for your name plate. Note: a copy of the letters I used for this project are now included in all mold orders: For block mold including template click hereFor the font template only click here.  You can also create your own by downloading the font online.
  • Roll out the fondant colors, cut out your template letters, cut the name, the black, yellow, and the red and black backgrounds using a small sharp knife.  For a more thorough steps check out or How to make a 2D Topper Tutorial Here.

Step 3. The Cake

  • Bake and cool your cake completely.  Torte it by slicing down the center of the layer for the filling and then freeze.  You can wrap or not (with plastic wrap or foil), this might depend on the types of other food items in your freezer.  For instance I had a cake-only freezer so I never needed to wrap when storing short term. Short term freezing will incorporate more moisture into your cake so don't worry about it drying out:)! Short term might be less than 2 days (depending on your freezer). However, my home freezer I wouldn't use like this past 2 hours.
  • When you are ready to start the decorating process pull the cake out of the freezer.  Next separate the layers carefully and fill with your desired filling.  
  • Use your chocolate ganache to coat sides and top of cake with a spatula.  If your ganache is too firm heat in the microwave for just a little bit and apply.  Use a bench scrapper to achieve nice clean sides and top.  Once your ganache is on if you want, to 'fix' the smoothness with the bench scrapper, heat a pot of water to dip and heat the bench scrapper.  
  • Refrigerate your ganached cake for about an hour to firm.  While this is refrigerating let's start the side blocks!

4.  Side Blocks

  • Roll out wide pieces using a roller with rings or using a pasta roller mixer attachement. Tip: To get a thicker piece than the #1 attachment setting, reverse the knob for a thicker piece.  
  • Let your the rolled out pieces dry preferably for about 1/2 hour to an hour.
  • While these are drying, create your cutting guide.  Using graph paper or engineering paper draw lines using a straight edge using the same width and length of your small molded block pieces (the dimensions of the final piece after you have cut it into 3).  If you bought a mold these templates are now included with each block mold order!:) For Block Mold including templates click here.
    • AFTER the pieces have firmed from the drying, cut out these pieces using a small knife, a straight edge, and your paper guide.  By having waited for the pieces to dry out this will go a lot faster:). 
    • These I like to cut as I need them.  I found these really tough to estimate quantity.

    5.  Put it all Together!!

    • Ok so this I think is the most fun part!  Apply a thin film of shortening to get your block pieces to stick.  I like to use high-ratio shortening (now comes in our cake kits!), because you can move your pieces around later if it needs tweaking.  
    • Next, start playing building blocks!  Create your own block color pattern on top of the cake.  
    • Overhang the border blocks just a tad so the side pieces will meet flush just under them.
    • Match the side pieces of the first row to the border pieces with the appropriate color.  
    • Cut side pieces where necessary
    • Fill the remaining rows of the side freestyle!
    • Apply green pieces on the board by using sugar glue. Simply make sugar glue with the following steps:
      • 1 part tylose powder, 1 part granulated sugar and 4-5 parts super hot water
      • Let sit for 15 minutes to set
    • After it is all together cut the cake board to fit (so no cardboard is showing beyond the green board pieces) and place the name topper on the cake.
    Whew, if you did all that CONGRATULATIONS!!
    Funnest. Cake. EVER! :-D

    I know this cake is a TON of work but your little one (or big one) will LOVE it!
    If you are looking to sell this kind of cake to someone I would recommend you charge $125+ as a beginner, $250+ developing, and $350+ experienced. These rates might be different depending on where you live.

    Happy Lego Cake Making!!



    1. Wow! Great tutorial! I have been looking for something exactly like this! I will be attempting this cake next month! Thanks so much.

      1. Thank you so much!! Good luck and I would love to see your project!:)

    2. Great cake! Can you get the mold supplies at any specialty shops. I'm running out of time and ordering online takes too long.

      1. Hi Brooke! Unfortunately I bought the mold supplies online:-/. I do have a mold ready to go, however, depending on where you are located it would take 2-3 business days with expedited shipping.

      2. Thanks. Unfortunately I need it Sunday

      3. No prob, for this last minute I recommend using a putty you can find in the clay section of Michaels Arts and Craft stores and a lego piece. It won't turn out as sharp and clean looking but it might do the trick just enough:)

    3. Simply awesome cake! You mentioned it´s a ganached cake. Would this work with white chocolate ganache too? When do you cover it with ganache? After it´s rested overnight or sooner than that? Thanks for any advice!

      1. Thank you! White chocolate ganache should work just as well (from what I have read white chocolate ganache is a little trickier to make but should work just as well:)). As for application I like to apply ganache right after filling it which I do right when I get it out of the freezer. Good luck!

      2. Thanks for the tip! I´ve worked with white ganache quite a bit for filling and underneath fondant, but never with real chocolate, so I´m a bit nervous. How long in advance can the cake be frozen? Won´t the chocolate "sweat" as the cake thaws? Once it´s covered in ganache, do you cigarette it again? thank you!!!

      3. oh gosh! refrigerate not cigarette!!! sorry!

      4. Sorry!! I just noticed I never responded!.. kinda late but oh well:-/ I just freeze the cake (without ganaching or filling it at all). Then as I apply the ganache I haven't noticed that it sweats as the cake thaws but that is with reg. ganache not white choco ganache.. my cakes do sweat when I buttercream but after a few hours that just dries right off:). Good luck if you haven't made it already!

      5. Buttercream cakes will not sweat if thawed in the refrigerator. Really important when using red and black colors. FYI

    4. hi can you give me some idea of how much of each colour fondant you used please?

    5. Hi Michelle! The way I would calculate this is use the number of pieces above... 50 green mold pieces, 23 yellow mold pieces, 13 blue mold pieces, 13 red mold pieces, and multiply that amount by the weigh of one mold piece. Also add about another 50% extra of the final amount for each color for the side blocks. I don't have the amounts because I never weighed them and originally made A LOT more than I thought I needed. It also depends on the color 'look' you are going for... for instance I really wanted to up the yellow:). However, the next time I do make it I am planning on weighing and updating this post!:) Thanks Michelle!

    6. Thanks a lot for this post! This is definitely a huge help for my own LEGO-cake. I was just wondering, since you let the top LEGO-pieces dry for some time, are they still "eatable" or are they sort of going to feel like hard candy? I kind of imagine the top of the cake to be really firm now and not as soft as fondant usually is.

      1. Hello! The lego pieces at the top are definitely still 'eatable' they are firmer but not like hard candy at all. It might not be as soft as regular fondant is but it really isn't too bad. Much luck would love to see your project!! (

    7. Hi, I was wondering if your 1/4 sheet cake is a 9x13?

    8. After cooling, leveling, and slicing at the middle of the layer, how long do you freeze cake…overnight or just for an hour or so? Do you need to cover it in freezer?

      You let the ganache sit out room temperature overnight?

      How long do you refrigerate with ganache on cake?

      The ganache works better than buttercream icing? It's crisper?

      Do you use buttercream for the middle filling? Or ganache?

      Your ganache recipe says to mix jam and water for the "glue" for fondant. What kind of jam tastes good with a cake? The Lego recipe calls for a fondant/water "glue." I'm assuming you using the fondant/water "glue" and the jam "glue" is for other cakes? Or does it not matter at all?

      Sorry for all the questions…I'm nervous about making the cake!

      1. Hello! I will do the best to answer:)...

        1. Freeze at least 6-8 hours overnight is best. I don't cover it because I have a whole cake freezer but you can cover if you would like. You can cover loosely with plastic wrap or foil or not at all. You should be fine for overnight if you don't cover tho:)

        2. Yes there are two ways for ganache... 1. Leave overnight to firm at room temp or 2. refrigerate uncovered (otherwise you will get condensation) for about an hour and it will be ready! Either works great.

        3. Refrigerate ganache on the cake about an hour

        4. Yes the ganache gives a very sharp and clean look (use a scraper on the sides if you can!) compared to buttercream

        5. For filling I use whatever is ordered.. feel free to use whatever filling you want:)!

        6. Yeah no worries! I doesn't really matter you just need a little stickiness (even using water works but that might be too sticky and would make the legos hard to move if you wanted to). These days I don't make that glue anymore but I used to use apricot. Also it is so little you really can't taste it to much. But really the best and easiest way is to use a thin film of shortening.

        If you have all these questions so might a lot of others so I will have to get my blog updated! thank you so much and good luck!!:)

    9. Thank you so much! I truly appreciate your help!!! :)

    10. My son doesn't like chocolate. Can I do a buttercream icing instead? If so what recipe do you recommend? If not what do you suggest? Also. How many days did this take you. I'm very nervous about making this cake myself! I want to give myself plenty of time for mistakes and redos. Thank you.

    11. Hi!!!
      Yours is my favorite cake i have found in a couple weeks of looking to attempt to make for my sons birthday in a month!! i love it! and great tutorial!!
      My question is, as your molds are not for sale anymore....i was already thinking of buying off amazon the silicone lego molds used for ice cubes/jello/crayons/etc and am wondering if those might work?? or if i should just make all my own molds, which im not even sure how well id do it??

    12. Hi -- Can you lay out the specifics of making the Lego name plate? I'm unclear on how you get the letters from the template to the fondant, and how you do the rest of the name plate. Thanks so much!

      1. Omg I am soo sorry to not have seen/replied to this! But will reply regardless:O). I have another blog post that follows a very similar approach:
        Good luck!

    13. I wanted to die when I made this cake. It was so precise that it was very difficult.

      1. I know this cake is sooo much work!! You are so brave to have made it!!:)

    14. Where is the fondant you say you sell on Etsy? I couldn't find it but I'm new to Etsy. Also... I didn't see a link to a YouTube video above. Thanks

      1. Hi Delia! I am sorry I just realized that I hadn't written back to your comment here but it sounds like I answered your questions already on Etsy:). Thanks!

    15. Hi, what size is the cake board? Is this cake just 1 layer? Or is it 1 layer cut in half and filled? Thanks

    16. Hi! I cut a half sheet cake board to fit. After arranging the green pieces around the cake I cut it accordingly. And yes this is one layer cake cut in half and filled:O), thanks!

    17. Thank you for this wonderful tutorial. Your instructions were so thorough that I braved this cake as my first ever attempt at fondant. I didn’t have time to get your mold ordered, so I used your instructions to also make my own LEGO mold. I did use your font from Etsy. Really happy with how it came out!

      1. You're welcome and thank you for sharing!!:-D Would love to see your beautiful cake<3

    18. I ordered the mold on etsy and am planning to make this for my son’s birthday June 3. How long does it take for the mold to arrive? I want this to be a surprise for him, which means I have to do everything at night. After reading other people’s comments, I’m starting to freak out at the difficulty. How many people did your cake feed? I’m hosting a small party. 4-5 kids. But I want the cake to look amazing. One of the kids doesnt like chocolate. Do you have a recipe for a different type of cake? What about a cake out of a box? I want to make this as easy for myself as possible. Thank you!!

      1. Hi! You should get this in 3-5 business days, I just took it to the post office today:). The cake is not difficult but it does take time. Breaking the tasks up in the evening should work very well! Once I made a wedding cake and made all the little pieces here and there so I wouldn't bother my husband with the kitchen lol. I would get started now with prepping the colored fondant itself. As for the cake ANY recipe should do just fine even box! I have done that myself:). Google "cake mix doctored recipes". I would LOVE to see your cake and how everything goes! Feel free to share here, on Etsy, our new site or facebook! Much luck he will LOVE it especially because you made it!!! (and the rectangular cake serves like 20-25 or so)

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    20. Where/how do you store the Lego blocks between making them and decorating the cake?

      1. Hi! Just store uncovered at room temperature perferably away from light (like on a tray in a cabinte)

    21. Hi there, just received my order from you for the lego mould and looking forward to making this cake for my son's 5th birthday. Question for you: given you make the top pieces 2 days in advance, is the cake difficult to cut (if the top pieces are too solid)?

      1. Hi and thanks for your order! No the cake is not difficult to cut into at all. But it will be nice and firm which is what makes the lego cake soo cool :). Of course this is with our Cake Couture fondant, I am unsure how other fondants like Satin Ice, Fondx, or Wilton will hold up. We actually now offer a cake kit for this cake as well which includes our fondant. Thanks and good luck with your cake project! We would love to see it and would love to share on our social if you decide you want to share it with us :). We can be reached at Have fun! :o)

    22. Love this cakes! Nice post. I like your views
      I think it can be helpful. Find best

      Lego piñata
      Unicorn smash cake

    23. I am so excited to attempt this cake! My question is about how to store the homemade marshmallow fondant after I have colored it but before I mold the blocks. Do I store it airtight like it would be if it had been store-bought, or do I actually want it to sit out and dry/harden a bit to work better with the mold? Room temp or fridge? Thanks!

      1. Hello, I am soo excited you will be attempting this cake, thank you for sharing! :) To store after coloring, keep it wrapped in plastic wrap.. airtight is perfect for either homemade or store-bought fondant. Also, if you'll be working with it in the next couple of days, I would keep the fondant at room temp, but otherwise I might put it in the fridge. But fondant keeps for a long time so it's ok if at room temp even longer :). I have a video to make to help with this cake. I will have to share that link when I finally put that together!


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