Rainbow Birthday Cake

Celebrate any special occasion with this show-stopping Rainbow Birthday Cake, bursting with vibrant colors and delicious flavors! Layers of moist cake in every color of the rainbow are stacked high and topped with a fluffy rainbow-hued buttercream frosting, making this cake a true masterpiece of celebration.

Ready Time

2 hrs 30 mins

Yields

9 servings

Ingredients

For the cake:
2 ¾ cups all-purpose flour
1 ½ cups granulated sugar
2 teaspoons baking powder
1 teaspoon salt
1 cup whole milk, at room temperature
2 large eggs, at room temperature
2 teaspoons pure vanilla extract
Food coloring in various colors (red, orange, yellow, green, blue, and purple)
For the buttercream frosting:
3 ¾ cups powdered sugar
1 ½ cups unsalted butter, at room temperature
2 teaspoons pure vanilla extract
Food coloring in various colors (red, orange, yellow, green, blue, and purple)
For the decoration:
Sprinkles or nonpareils in various colors

Instructions

Preheat your oven to 350°F (175°C).

Grease and flour three 9-inch (23cm) round cake pans.

In a medium-sized bowl, whisk together the flour, sugar, baking powder, and salt.

Set aside.

In a large mixing bowl, whisk together the milk, eggs, and vanilla extract.

Gradually add the dry ingredients to the wet ingredients, whisking until smooth.

Divide the batter into six portions and color each portion a different color of the rainbow – red, orange, yellow, green, blue, and purple.

Pour each colored batter into a prepared pan and smooth the tops.

Bake for 20-25 minutes or until a toothpick inserted in the center comes out clean.

Let the cakes cool in the pans for 5 minutes before transferring them to a wire rack to cool completely.

For the buttercream frosting, beat the powdered sugar and butter until light and fluffy.

Add the vanilla extract and mix well.

Divide the frosting into six portions and color each portion a different color of the rainbow.

To assemble the cake, place one cake layer on a serving plate and spread a layer of frosting on top.

Repeat this process with the remaining cakes and frosting, creating a rainbow effect.

Decorate the top and sides of the cake with sprinkles or nonpareils in various colors.

Notes

Use high-quality food coloring to ensure vibrant colors. Make sure to grease and flour the pans well to prevent the cakes from sticking.

For an ombre effect, you can gradate the colors of the cake layers from darkest to lightest.

If you’re not comfortable making a six-layer cake, you can also make a three-layer cake with two colors per layer. To ensure the cakes bake evenly, try to get the batter as close to the same weight as possible.

Let the cakes cool completely before assembling the cake to prevent it from becoming too crumbly.

If you find that your frosting is too thin, refrigerate it for about 10 minutes to firm it up. You can also customize the sprinkles or nonpareils to match the birthday person’s favorite colors.