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Rainbow Sheet Cake

This Rainbow Sheet Cake is a cheerful, colorful dessert that’s perfect for birthdays, parties, or any celebration. With layers of vibrant rainbow batter and creamy frosting, it’s as fun to look at as it is to eat.
Print Recipe
Prep Time 25 minutes
Cook Time 40 minutes
Cooling Time 1 hour
Total Time 2 hours 5 minutes
Servings 12

Ingredients
  

For the cake:

  • ¾ cup unsalted butter softened
  • 2 cups white sugar
  • 3 large eggs
  • 1 tablespoon vanilla extract
  • 2 ¾ cups all-purpose flour
  • 1 tablespoon baking powder
  • ½ teaspoon salt
  • 1 ¼ cups milk
  • Gel food coloring red, orange, yellow, green, blue, purple

For the frosting:

  • 8 ounces cream cheese softened
  • ½ cup unsalted butter softened
  • 4 cups confectioners’ sugar
  • 1 teaspoon vanilla extract
  • Food coloring for rainbow piping

Instructions
 

  • Preheat oven to 350°F (175°C). Grease a 9×13-inch pan.
  • In a large bowl, cream butter and sugar until fluffy. Add eggs and vanilla, beating well.
  • In another bowl, whisk flour, baking powder, and salt. Add dry ingredients to wet, alternating with milk, beginning and ending with flour.
  • Divide batter into six bowls. Tint each portion with a different gel color.
  • Dollop colored batters randomly into the prepared pan. Use a knife to swirl slightly if desired.
  • Bake for 35–40 minutes, or until a toothpick comes out clean. Cool completely.
  • For frosting, beat cream cheese and butter until smooth. Add sugar and vanilla, mixing until fluffy.
  • Spread frosting evenly over cooled cake. Use tinted frosting to pipe rainbow accents on top.

Notes

  • Use gel food coloring for bold, vibrant colors.
  • Don’t over-swirl the batter or colors will blend together.
  • Chill the frosted cake for cleaner slices.
  • Leftovers keep well in the refrigerator for 3–4 days.