Rainbow Layer Cake

Prep Time: 30 Minutes
Cook Time:
Total Time: 2 Hours
Servings: 10

You’ll be proud to make and serve a cake that’s as much fun as this one. Rainbow layer cake is surprisingly easy to create, thanks to a little help from Betty Crocker™ Super Moist™ vanilla cake mix and Betty Crocker™ classic gel food colors.

Ingredient List

  • Small check mark in a circle icon 2 boxes Betty Crocker™ Super Moist™ vanilla cake mix
  • Small check mark in a circle icon 2 cups water
  • Small check mark in a circle icon 1 cup vegetable oil
  • Small check mark in a circle icon 6 eggs
  • Small check mark in a circle icon 2 packages (2.7 oz each) Betty Crocker™ classic gel food colors
Buttercream Frosting
  • Small check mark in a circle icon 1 cup shortening
  • Small check mark in a circle icon 1 cup butter, softened
  • Small check mark in a circle icon 1 bag (2 lb) powdered sugar
  • Small check mark in a circle icon 2 teaspoons vanilla
  • Small check mark in a circle icon 3 to 4 tablespoons milk


  1. Heat oven to 350°F. Spray 3 (8-inch) round cake pans with cooking spray.
  2. In large bowl, beat cake mix, water, oil and eggs with electric mixer on low speed 30 seconds, then on medium speed 2 minutes, scraping bowl occasionally. Divide batter evenly among 6 small bowls, about 1 1/3 cups each.
  3. Using food colors, tint batter in 1 bowl blue, 1 bowl red, 1 bowl green, 1 bowl yellow, 1 bowl orange (using red and yellow) and 1 bowl purple (using blue and red).
  4. Refrigerate 3 colors of batter until ready to bake. Pour remaining 3 colors of batter into cake pans.
  5. Bake 18 to 20 minutes or until cake springs back when touched lightly in center and begins to pull away from side of pan. Cool 10 minutes. Remove from pans to cooling racks; cool completely.
  6. Wash cake pans. Bake and cool remaining 3 cake layers as directed.
  7. In large bowl, beat shortening and butter with electric mixer on medium speed until light yellow. On low speed, gradually beat in powdered sugar. Beat in vanilla. Add milk, 1 tablespoon at a time, beating until frosting is smooth. Beat on high speed until light and fluffy.
  8. Trim rounded tops off cakes to level, if needed. On serving plate, place purple cake layer. Spread with frosting to within 1/4 inch of edge. Repeat with blue, green, yellow, orange and red cake layers. Spread light coat of frosting on top and side of cake to seal in crumbs, then frost with remaining frosting.

Recipe Tips

  • Cake batter is stable enough to wait in the fridge until the first three layers are baked. Be sure to rinse the pans in cool water and dry them well before scraping the rest of the batters into the pans. Bake as directed. If you only have two 8-inch cake pans, bake the cakes in three batches instead.
  • To make sure cake layers bake up level, be sure to evenly divide the batter between the bowls when coloring. Using half shortening and half butter for the buttercream frosting ensures that it will stay firm enough at room temperature. Make it ahead and chill it for a while to firm it up before assembling the layers.
  • For guaranteed easy unmolding, line each pan with baking parchment. Set one of the pans on the paper and trace a circle around the base with the tip of a sharp paring knife to create a round that fits inside the pan; repeat to make enough for all the layers.
  • For a deeper red color, add a teaspoon or two of unsweetened baking cocoa to the red batter
  • Make this a party cake and switch up the colored layers as requested by the birthday girl or boy