How to Make a Fun-Filled Rainbow Sprinkle Layer Cake

Even more fun: It's got marshmallow fondant!

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Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Photo By: Heather Baird SprinkleBakes.com

Dessert to Dye For

This colorful cake is what dreams are made of. It's coated in sprinkles and marshmallow fondant details, and is even brighter on the inside cut it open to reveal six layers of fun! Follow along to learn how to make this over-the-top treat.

Get the Recipe: Rainbow Sprinkles Layer Cake

Prepare the White Cake Batter

This recipe begins with white cake batter, which requires lots of egg whites — so stock up! They give the cake structure (helpful for sturdy layering) and keep the batter light in color, which is great for dying. Get the fulll instructions in the recipe.

Fold in the Color

Divide the batter evenly into six bowls (about 2 cups per bowl). Tint each bowl with a couple drops of gel food color in red, orange, yellow, green, blue, and violet hues. Fold the color in gently so you don’t deflate the cake batter.

Bake Away

Place the batter in greased 8-inch cake pans and bake for about 20 minutes. You’ll know the cakes are done when a toothpick tester inserted near the center comes out clean.

Level the Layers

Level each cake so that the layers are all the same size and even (not domed) across their tops. You can use a cake leveler if you hve one, but a serrated knife also works well.

Build and Frost

Begin building the cake with the violet layer. Cover it with a thin layer of buttercream frosting followed by the blue layer. Continue alternating cake layers and frosting with the remaining green, yellow, orange and red layers.

Straighten Up

Once the layers are stacked, check to make sure the cake is even on all sides and doesn’t lean or wobble. If it feels a little wobbly, consider pushing a long plastic straw or wooden dowel through the cake to stabilize it. Simply cut the straw or dowel to the cake’s height and insert it down the center through all of the cake layers.

Frost Smoothly

Cover the whole cake with buttercream and use a bench scraper or cake smoother to even it out. The finished result should look smooth and tidy.

Scoop Those Sprinkles

Place rainbow sprinkles in a large baking pan or dish, and then place the cake inside the dish. Use your hands to scoop sprinkles and press them gently onto the sides of the cake.

Chill Out

Continue to press sprinkles up the sides of the cake until it’s about 2/3 covered. When the sprinkles are applied to your liking, transfer the cake to the refrigerator to chill.

Melt Marshmallows

Marshmallow fondant is easy to make and tastes wonderful! Get the full instructions in the recipe. You start by melting mini marshmallows and 1/2 tablespoon of water in the microwave until it can be stirred smooth.

Put Down the Spoon

Add powdered sugar to the melted marshmallow and mix until well incorporated. The fondant will become quite thick and too difficult to stir. At this stage, abandon your spoon and get ready to use your hands.

Knead It Out

Knead the fondant on a greased surface until it is smooth and pliable. It should be a little stiff and hold its shape well when you roll it into a ball. If the fondant is too soft or relaxes into a puddle, then knead in more powdered sugar.

Tint the Fondant

Divide the fondant into six equal portions and tint each with gel food color. Wear gloves to knead in the color to avoid staining hands.

Stamp Shapes

Roll each piece of fondant to 1/8 inch thickness and use a small triangle cutter (about 1 1/2-inches) to stamp shapes from each color.

Create Bunting

Place the triangles end-to-end to create bunting that "hangs" like a swag. The pieces should stick naturally, but if they don’t, dot the backs of the triangles with water and then place again.

Pipe Stars

Place the rest of the buttercream in a piping bag fitted with a small open star tip. Pipe stars around the top and bottom edges of the cake, and in the top center of the cake.

Make It Pop

Add round candies in alternating rainbow colors around the top edge of the cake, placing one on top of each piped star. Sprinkle the center with more rainbow sprinkles.

Add the Finishing Touches

For a final finishing touch, sprinkle rainbow nonpareils around the bottom edge of piped frosting.