You don’t need fancy cake decorating skills to make an awesome LEGO birthday cake! This easy LEGO cake looks like one giant LEGO brick and requires no fondant or special cake pan. All you need is a loaf cake, frosting and a few marshmallows to create the LEGO studs on top.
It’s an easy homemade birthday cake for any LEGO fan, and you can customize the frosting color to match your LEGO party theme.
No fondant: Marshmallows create the LEGO studs, so you don’t need any special cake-decorating skills.
How to Make an Easy LEGO Cake
Instead of making a cool cake with lots of LEGO bricks like a building set, I decided to make a LEGO cake that was just one extra large LEGO brick. A cake with a lot of detail could be a very frustrating endeavor. So I went simple and big with one giant LEGO brick.
A regular loaf pan creates the rectangular LEGO brick shape, so there’s no need to buy a specialty LEGO cake mold.
What You Need for a LEGO Brick Cake
Start by baking your cake in a 1-lb loaf pan. Use your favorite homemade cake recipe or keep it easy and buy a box of cake mix – Don’t worry I won’t tell! 🙂
I let the cake cool briefly before dumping it out of the pan. But like most cake recipes, I recommend cooling the cake completely before frosting it.
How to Make LEGO Studs Without Fondant
Now you could totally try and make the LEGO studs out of fondant but why, when marshmallows are way easier to use! For this cake, cutting standard marshmallows in half worked well to create the appropriate size for the LEGO studs to place on top of the brick.
Use food coloring to create whatever LEGO brick color you want. This is a fun way to theme this cake to any LEGO party theme. For example, making pink or purple frosting would work great for a LEGO Friends birthday party. Or go with a primary color for a more LEGO duplos theme.
The Trick for Smooth LEGO Cake Frosting
The first time I made this cake, I spread buttercream over the cake and marshmallows. It worked, but it was messy and wasn’t as smooth as I wanted. The next time, I warmed store-bought frosting and poured it over the cake instead. It was much easier and gave the LEGO brick a smoother finish.
Easy LEGO Cake Idea
How to create a LEGO brick cake using your favorite cake recipe or a cake mix. The flavor doesn't matter, you can make this with a chocolate cake, yellow cake or whatever flavor you your LEGO fan likes.
All you need is marshmallows and frosting to pull off this simple LEGO cake idea.
Ingredients
- Cake Mix
- Frosting
- 4 Marshmallows
Instructions
- Grease a 1-lb loaf pan before pouring cake batter in. Use a box of cake mix or your favorite homemade recipe.
- Follow cake directions for baking and allow to cool slightly before removing cake from pan by turning it upside down. Allow it to cool completely before decorating it.
- Cut 4 marshmallows in half and arrange them on top of the cake to look like a little nub on top of LEGO brick. The cut side of the marshmallows will be slightly sticky, helping it stick to the top of the cake.
- Place the cake on a wire rack on top of a large cutting board or cookie sheet.
- Warm the frosting up in the microwave until it's smooth and stirs easily. I suggest stirring after 30 second intervals to check consistency.
- Pour frosting over the top of the cake. Scrape up the excess underneath and reheat it to pour again if necessary. Use a spatula to cover any places that are a little thin on frosting.
Notes
Don't overheat the frosting. You want it runny enough to pour over the cake but not too hot. Let it cool down before pouring it on top of cake if it's too hot.
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LEGO Birthday Cake Decorating Ideas
To make it extra special, display it on a LEGO base plate and add a few Minifigures. I suggest placing a piece of parchment paper under the cake to keep things cleaner. You can even add buildable candles to the cake with these fun LEGO inspired candles.
Are you for LEGO birthday party ideas? I have a post dedicated to easy LEGO party ideas include decorations, activities, and party favors. I hope it helps you plan an easy and fun lego-themed birthday party.
More Easy LEGO Birthday Party Ideas
Try decorating with candy lego bricks for a fun cake idea. I’ve found a few different kinds of edible legos made of candy bricks. It would be pretty easy to add those to the top of a regular cake for an even easier design.
And if you are still reading this and don’t love these ideas or don’t think you can do them ( I promise you can)! Then you might want to try connecting with professional cake decorators for a color LEGO birthday cake. Just know it will be costly but for some parents its totally worth it.
- Easy LEGO Party Ideas
- LEGO brownies
- LEGO Batman cookies
- Easy Birthday Cake Ideas for Kids
- LEGO Movie costume ideas
This post was originally published October 22, 2015.
Tiffany MacSlarrow says
Hi! Can I make this the night before? Would it need refrigerating if so?
Karen says
I do make my cakes ahead and do refrigerate them because I use buttercream frosting.
Katrina Young says
Hi Karen! Do you use a homemade buttercream or store bought? If it’s your own, do you mind sharing a recipe? I used my homemade frosting and warming it turned it into a globby mess. Thank you!
Karen says
For this I used store bought, Although in general I do love homemade frosting.