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Rainbow Layer Cake

Rainbow Layer Cake for Birthdays

This cake really speaks for itself and everyone will be so impressed when you cut in and reveal 6 beautiful layers of delicious homemade cake. 

You can use it for any occasion and make it any colors you want! This rainbow version was made (by me) for my 28th birthday. I've also made it in orange and yellow for my son's birthday and pink and purple for my daughter.

You can use natural dyes to make this cake. 

  • Duration
  • Cook Time
  • Prep Time
  • 10-12Servings


  • 3 cups all-purpose flour
  • 4 teaspoons baking powder
  • ½ teaspoon salt
  • 1 cup unsalted vegan butter, room temperature
  • 2⅓ cup sugar
  • 5 egg whites, room temperature
  • 2 teaspoons vanilla extract
  • 1½ cup soy milk, room temperature
  • ⅛ teaspoon each: red, orange, yellow, green, blue and purple food coloring
  • 3 containers pre-made vanilla frosting


1. Preheat 1-2 ovens in to 350 degrees. Prepare six 9-inch-round foil pans with vegetable spray, then line the bottom of each with parchment paper and spray again.

2. In a large bowl, whisk together the flour, baking powder and salt. In an electric mixer, cream together the margarine and sugar. Slowly add the egg whites and mix until well combined.

3. Add the vanilla and mix until fully incorporated. Next, mix in the flour mixture and soy milk in two alternating additions, beginning with the flour and ending with the milk.

4. Now comes the really fun part! Divide the batter evenly between six medium bowls. Each bowl contains around 1 cup of batter.

5. Wearing gloves,add 1/8 tsp. of each color of food coloring to its designated bowl and whisk away. Add a bit more for the red batter, since I don't think the color is bright enough with just 1/8 tsp. Between each bowl, wash the whisk so the colors don't combine.

6. Transfer each color to the prepared cake pans then move those pans in to the ovens. If you don’t have room in your oven for all six pans, you can bake them in batches. The cakes bake for only 15 minutes, so if you need to work in batches, it won’t take too long.

7. Remove the cakes from the oven and transfer them to a wire rack. After cooling for 10 minutes, invert the cakes onto a wire rack; re-invert and let cool completely.

8. Martha Stewart suggests trimming the tops of the cakes to make them level, but I skip this step since my cakes are usually fairly even. You are welcome to trim the tops using a serrated knife, if you want! Place four strips of parchment paper around the perimeter of a 10 inch cake circle, then place the purple layer in the center. Spread 1 cup of frosting over the first layer with a spatula so it extends just beyond the edges of the cake.

9. Repeat the process with the blue, green, yellow and orange layers.

10. Place the remaining red layer on top, bottom-side up.

11. Sweep away any loose crumbs then cover the top and side with a thin layer of frosting with a spatula, also using any of the excess frosting visible between the layers. Refrigerate the cake for 30 minutes, until it set.

12. After 30 minutes, take the cake out of the fridge and cover it again with the remaining frosting.

All done!