Easy Roblox Birthday Cake

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My son absolutely loves the game Roblox. Roblox is an online game creation system platform that allows users to design and play their own games, as well as play all sorts of different games designed by other users. My son loves to play it on his iPad and I also have it on my cell phone so we can play games together on Roblox. Roblox is a free platform although there are many in-game purchasing opportunities as well.

Each player on Roblox can design their own avatar and my son loves to change his around and make it silly. Right now I think his avatar includes a TV on his head and wings made of newspapers.

Birthday Cake Ideas

Every year I try to do a fun cake for my son as I love incorporating the things he loves into his birthday celebrations. One year I wanted to incorporate the Marvel characters, think Ironman, Thor, Spiderman, etc. Another year I incorporated Minecraft into it. This year I wanted to make it something to do with Roblox. I turned to my favorite resource, Pinterest, for ideas. After looking through many different cakes, I decided I wanted to try and make one with my son’s avatar. Thankfully at the time of his birthday, he hadn’t yet added the TV and wings to his avatar and his avatar was a little simpler:

Designing the Birthday Cake

I needed to come up with a design and what I wanted to do exactly. I decided to keep it simple, go with a square cake and create a fondant Roblox avatar. I wasn’t going to try and make anything 3 dimensional so I decided to simplify the design by making it all out of rectangle and square shapes similar to the picture below:

I would then free-hand the hair, ears, mouth, sunglasses, and t-shirt decorations.

Finding the Right Fondant

Every time I’ve eaten fondant it has been absolutely awful. It doesn’t have much flavor and tastes pretty bland. The store-bought kind I found online didn’t have good reviews. It also sounded like it wasn’t easy to work with so I went in search of an easy fondant recipe that would also taste good and I could easily make at home. I found the following recipe online and it was super easy.

Marshmallow Fondant


  • 1 pound of Mini Marshmallows
  • 1/4 – 1/2 cup water
  • 1/2 cup Crisco vegetable shortening (for counter and hands as fondant can be sticky)
  • 2 pounds of powdered sugar
  • 1-2 teaspoons clear vanilla extract or other flavoring of your choice
  • Gel Food Coloring (if you’re going to make different colored fondants). I found the best food coloring on Amazon and I now swear by it as it blends easily and has a wide variety of colors. It is called AmeriColor Gel Food Coloring


  1. Pour marshmallows in a microwave-safe bowl
  2. Pour water over marshmallows and microwave for 30-60 seconds
  3. Remove from microwave and stir. If not smooth, microwave for additional time 15-30 seconds at a time until smooth.
  4. If you want to make multiple colors of fondant, now would be the time to add the food coloring. Stir desired color in until combined thoroughly. You can add food coloring later once the fondant is combined, but it isn’t as easy to get the color completely combined. If you’re making multiple colors you’ll either have to (A) make multiple batches of fondant, coloring each one as you go, or (B) making one huge batch of white fondant, breaking it up into sections, and adding different colors as needed.
  5. Add powdered sugar to marshmallows and using a rubber spatula, begin to stir. And stir. And stir. And stir some more. Once you’ve stirred as much as you can with the spatula, rub Crisco all over your hands and counter, cutting board, or pastry mat (because fondant is SUPER sticky) and begin to knead the fondant. Knead the fondant until it’s smooth. It’s best to refrigerate fondant overnight so it’s easier to work with when you are ready to create the design.
  6. To refrigerate, shape fondant into a smooth ball, rub Crisco very lightly on the fondant ball, and cover with plastic wrap making sure to leave no air bubbles. Refrigerate overnight or until you’re ready to begin cake decorating.

Making the Cake

My son loves chocolate cake and vanilla frosting. I’m all for making things as easy as possible so I definitely use boxed cakes and pre-made frosting. My favorites are:

Make the cake as per box instructions, allow to cool, cover and refrigerate overnight. I bought two boxes and doubled the recipe because I wanted to do a three layer square cake. I used square cake pans I found on Amazon:

Assembling the Cake

Remove cakes from the refrigerator and unwrap. Prepare the frosting by spooning out the frosting into a bowl and, if you want a different color than the original frosting, adding the gel food coloring of choice. Mix thoroughly and set aside. I find the whipped frosting works really well in incorporating different colors. They are also lighter than regular frosting which I like. It’s all a matter of personal preference though.

Turn out all three cake layers onto a cutting board. When you bake a cake, they usually puff up and come out of the oven a bit rounded on top. In decorating a cake, it’s difficult to get the cake looking like you want if it’s not flat so I recommend cutting off a thin layer on top to make each layer flat.

Using a sharp knife or a cake leveler, slice off the very top of each cake layer so all three are flat. Place the first layer on a cake plate or board. Frost the top of the first layer and place the second layer on top of the frosted first layer. Frost the second layer and place the third layer on top. Using a sharp knife, trim up all the sides of the cake so the layers are lined up and straight. Once the cake sides are to your liking, frost the entire cake.

Working with Fondant

Remove the fondant from the refrigerator and unwrap from the plastic wrap. Grease the surface you will be working on – counter, cutting board, pastry mat – as well as your hands. Begin kneading the fondant to soften it up. Flatten fondant out and using a sharp knife, cut the desired shapes needed for the decorations. For my Roblox cake, I was cutting out various rectangles and squares and assembling them directly on the cake. As the fondant softens and warms, it gets stickier so have some powdered sugar nearby and add to fondant as needed to keep it firm

I cut out the rectangles and squares and then by freehand made the hair, ears, mouth, sunglasses, and t-shirt decoration (sleeve stripes and the front of the shirt). Instead of the exploding bricks, I decided to just use the first initial of my son’s name. I was happy with the final result:

Roblox avatar on birthday cake

I had a lot of fun making this cake and learned a lot about working with fondant. I love being creative and making things that my family enjoys and interests them. This birthday cake was a hit and I had a very happy birthday boy!


Roblox Birthday Cake

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