Tulo

Rainbow Cake Recipe

Splitting one vanilla batter into six bowls and tinting each with gel coloring keeps every layer the same texture and flavor, so the cake reads as a single dessert rather than six different cakes stacked together; baking in batches of three in the same pans keeps the layers uniform in height.

Prep
60 min
Cook
75 min
Total
180 min
Servings
16

Ingredients

Servings16
  • 3 cups cake flour
  • 2 1/4 cups granulated sugar
  • 1 tbsp baking powder
  • 3/4 tsp salt
  • 1 cup unsalted butter, softened
  • 1/2 cup vegetable oil
  • 6 whites large egg whites
  • 2 tsp vanilla extract
  • 1 cup buttermilk
  • 6 small bottles gel food coloring (red, orange, yellow, green, blue, purple)
  • 1 1/2 cups unsalted butter, softened (for frosting)
  • 12 oz cream cheese, softened
  • 6 cups powdered sugar

Nutrition per serving

Calories
717
Protein
5g
Carbs
86g
Fat
40g

Based on the recipe as written, one serving. Recalculates if you swap an ingredient above. An estimate only, exact values depend on the specific ingredients used.

Need different units or a different yield? Try our Conversion Calculator →

Instructions

  1. 1Preheat the oven to 350°F (175°C). Grease and flour three 8-inch round cake pans and line the bottoms with parchment.
  2. 2In a medium bowl, whisk together the cake flour, baking powder, and salt.
  3. 3In a large bowl, beat the softened butter and sugar until light and fluffy, 3-4 minutes. Add the oil and vanilla and mix to combine.
  4. 4Add the egg whites one at a time, beating well after each addition.
  5. 5Add the dry ingredients in three additions, alternating with the buttermilk in two additions, beginning and ending with the dry ingredients. Mix just until no streaks of flour remain.
  6. 6Divide the batter evenly among six bowls, about 1 1/3 cups each. Tint each bowl a different color using gel food coloring: red, orange, yellow, green, blue, and purple.
  7. 7Pour three of the colors into the prepared pans, about 1 cup batter per pan. Bake 12-14 minutes, until a toothpick inserted in the center comes out clean. Cool in the pans 10 minutes, then turn out onto wire racks to cool completely.
  8. 8Wash, re-grease, and re-flour the pans, then repeat with the remaining three colors of batter.
  9. 9Make the frosting: beat the butter and cream cheese together until smooth. Add the powdered sugar in two additions, beating on low until incorporated, then beat in the vanilla and a pinch of salt until fluffy.
  10. 10Level any domed layers with a serrated knife, then stack the layers in rainbow order (red, orange, yellow, green, blue, purple), spreading about 1/2 cup of frosting between each.
  11. 11Apply a thin crumb coat of frosting over the whole cake and chill it for 20 minutes, then frost the outside with the remaining frosting.
How to Frost a Cake

Tips & variations

  • Bake in batches of three rather than trying to fit all six pans in the oven at once; crowding the oven causes uneven rising and inconsistent color intensity between layers.
  • For sharper color lines when the cake is sliced, chill the fully assembled cake for at least an hour before cutting.
  • Swap the cream cheese frosting for a plain vanilla buttercream if a firmer, pipeable frosting is needed for decorating.
  • Only have two cake pans? Bake the six colors in three separate batches instead of two, washing and re-prepping the pans between each.

Storage & reheating

Store the frosted cake covered in the refrigerator for up to 5 days; the cream cheese frosting is not shelf-stable at room temperature for more than a couple of hours. Let slices sit at room temperature for 15-20 minutes before serving so the frosting softens. Unfrosted layers can be wrapped individually in plastic and frozen for up to 2 months; thaw in the refrigerator before assembling.

Tips from the Tulo kitchen

  • Weigh out the batter into each bowl with a kitchen scale rather than eyeballing it, since uneven amounts show up as layers of different thickness once the cake is sliced.
  • A bench scraper held flat against the sides while spinning the cake stand gives a smoother final coat than a spatula alone.

FAQ

Why did my rainbow cake colors turn out muddy or dull?

Liquid food coloring is too diluted to produce true colors in a batter this pale; gel or paste food coloring gives saturated color without thinning the batter.

Can I make this cake with fewer than six colors?

Yes. Three or four colors still read as a rainbow effect when sliced and cut the baking time in half since fewer batches are needed.

Do I need three cake pans for this recipe?

Three pans let two batches cover all six layers; with only one or two pans, plan on baking three to six separate batches and add extra time for the pans to cool between uses.

Can I use a boxed cake mix instead of a scratch batter?

Yes, two batches of a boxed white cake mix will fill six 8-inch layers; split each batch into three bowls and tint as directed.

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