One of the most popular decorative cakes is the rainbow cake. This colorful, complex display of baking is a well-known recipe among professionals, apprentices, and even your everyday moms. While it might seem challenging to make, a rainbow cake is actually quite easy and fun to make. Follow up with some simple frosting and confetti and voila. Instant happiness.

Most rainbow cakes use a pound cake batter formula which is layered and glazed with buttercream frosting and topped with confetti. However, In today's recipe, we will be doing a variation based on a classic sponge cake.

Don't worry! Sponge Cake is also quite simple since it only requires three main ingredients: flour, sugar, and whipped eggs (for leavening).

The recipe

Batter Ingredients:

  • 6 0z cake flour, sifted
  • 11 oz granulated sugar
  • 10 eggs
  • 1 1/2 vanilla extract
  • 2 tsp Cream of Tartar
  • 6 different food coloring

Buttercream Ingredients:

  • 1 lb unsalted butter, softened
  • 2 lb powdered sugar, sifted
  • 2 tsp vanilla extract
  • 2 tsp fine confetti


  1. Line the bottoms of six springform pans with parchment paper. Don't grease the sides of the pans. Set aside.
  2. Sift the flour and 6 oz of the sugar together. Set aside.
  3. Separate the eggs, placing the yolks and whites in separate mixing bowls. Whip the yolks and vanilla on high speed until thickened, doubles in volume and form ribbons.
  4. Place the bowl of egg whites on the mixer stand with balloon attachment and beat until foamy and forms soft peaks. Add the cream of tartar and one ounce of the sugar. Whip at medium speed until the whites are glossy and form stiff but wet peaks.
  5. Remove the bowl from the mixer. Using a rubber spatula, fold the egg yolks into the whites. Gradually add the remaining sugar over the mixture and fold in gently.
  6. Gently add 1/3 of the sifted flour to the batter and fold in. Repeat the process until all flour is incorporated. Don't over mix the batter.
  7. Divide the batter evenly among two bowls.
  8. Take one of the bowls filled with batter and pour it into three of the prepared pans. Choose three of the food colors and add a few drops to the desired pan. Using two separate spatulas, fold in the colors into the batters gently and add more if needed to get the right hue. Gently smooth the surface of each batter.
  9. Bake in a pre-heated oven at 190°C until the cake for 30 minutes or the cakes are springy to touch and a toothpick or small knife comes out clean when inserted.
  10. Allow the cakes to rest in their pans until completely cool, approximately two hours.
  11. Run a thin metal spatula or butter knife around the edge to each pan to remove the cakes.
  12. Repeat steps 8 - 11 with the second bowl of batter and remaining two food colors.
  13. Once all cakes are done, use a long cake knife to shave the top of each cake to leave a flat even surface.
  14. To make the buttercream, put all the ingredients in a mixing bowl and beat with the stand mixer or hand mixer until smooth and fully incorporated. Don't overbeat.
  15. To glaze the cakes, place a cake on a rotating cake stand. Using a metal spatula, place 1/12 portion of the icing on the top of the cake. Slowly twirl the cake stand while spreading the buttercream with the spatula. Smooth down the surface evenly. Take another 1/12 portion of buttercream repeat the process with the sides of the cake.
  16. Stack another cake on top and repeat the glazing technique. Repeat until all cakes are stacked and glazed on top. Use the spatula to smooth down the buttercream on the joined sides of the cake evenly. Finish by topping the layered sponge cake with the confetti.
  17. Serve immediately or store the cake in a refrigerator.