Triple Layer Rainbow Birthday Cake
Triple Layer Rainbow Birthday Cake
Recipe type: Dessert, Cake
  • Cake
  • 2 white box cake mixes + ingredients to make them per package instructions (probably water, oil, and eggs)
  • Gel food coloring, rainbow colors (can be found online or in craft stores like AC Moore and Michaels)
  • Buttercream Icing
  • 2 sticks of butter, room temperature
  • 8 cups of confectioner's sugar
  • 1 tablespoon of vanilla extract
  • 6-8 tablespoons of milk
  1. Cake: Preheat oven as directed on cake mix box.  Grease and flour, or use baking spray, three 9" round cake pans.
  2. Prepare cake mixes as directed on the box.  Divide the batter evenly into 6 bowls.  A tip to make it easy: Use a 1 cup measuring cup and scoop 1 cup of batter into each bowl, then divide the rest of the batter into each of the 6 bowls just by eyeballing it. It doesn't have to be exact but this is an easy way to get it close.
  3. Use ½ teaspoon of gel food coloring to color the batter in each of the 6 bowls.  You do not need to measure this out. Just eyeball it by getting a small hunk on food coloring on the end of a knife and mixing it in. A little goes a long way.  I used pink, orange, yellow, green, blue, and purple.  Feel free to come up with your own color patterns to mix it up.
  4. Fill the cake pans with batter by layering the colors randomly.  Try to get the batter divided evenly among the 3 pans.  If it's not perfect, that's okay.
  5. Bake all three cakes in the oven as directed on the cake mix box.  If you haven't poured them exactly evenly, keep watch  because they might finish cooking at different times. I pulled all three of my layers out at different times because they weren't exactly even.
  6. Allow the cakes to cool on a wire rack.
  7. Icing: Beat the butter with a mixer until slightly fluffy, maybe 20 seconds.
  8. Add the vanilla and mix.
  9. Add the confectioner's sugar about 2 cups at at time, alternating with a tablespoon of milk until you get the consistency you want.  Don't make it too runny or it will drip off the cake.
  10. If it's too stiff, add more milk. Too runny, add more sugar.  Mix until smooth.
  11. Assembly: Line your cake plate with wax paper.  I overlap three pieces to form a triangle shape in the middle of the plate.  This will keep your plate clean when you're done icing. (A trick my Mom taught me!)
  12. If your layers are at all uneven, put the smallest, flattest layer on the bottom.  Ice the top.
  13. Add the second layer and ice the top.  This should be the next biggest layer if your layers are uneven.
  14. Add the third layer and ice the sides of the entire cake. Then ice the top.
  15. Tip: If your layers bubble up in the middle you can either use a serated knife to cut the bubble off and make them flat, or add more icing around the edges of the layers to fill in that gap. (I vote for more icing.)
  16. Decorate as desired. Rainbow sprinkles are fun!
  17. Gently pull the pieces of wax paper out and you'll be left with a clean cake plate!
Recipe by See Mom Click® at