Rainbow Cake with Orange Buttercream

Rainbow Cake with Orange Buttercream


·         2 ¼ cups granulated sugar

·         8 ounces cream cheese, room temperature

·         ½ stick (4 tablespoons) unsalted butter, room temperature

·         4 eggs

·         2 teaspoons vanilla extract

·         1 teaspoon orange extract

·         3 cups all-purpose flour

·         1 teaspoon kosher salt

·         1 teaspoon baking powder

·         1/8 teaspoon baking soda

·         Zest of 1 navel orange

·         1 1/3 cups whole milk (or a combination of liquid, such as the juice from the orange you zested, plus milk, cream and/or buttermilk, to equal 1 1/3 cups altogether)

·         Food coloring: red, orange, yellow, green, blue and purple

Orange buttercream:

·         2 ½ cups (5 sticks) unsalted butter, room temperature

·         Zest of 1 navel orange

·         5 cups powdered sugar

·         3 tablespoons meringue powder

·         4-5 tablespoons milk

·         1-2 teaspoons orange extract

·         Rainbow sprinkles

Bake the Cake:

Preheat the oven to 350.  Spray the bottoms of 6 eight-inch pans with non-stick baking spray, line with parchment paper, then spray the paper as well.  Set aside.

In the bowl of your stand mixer fitted with the paddle attachment, beat the sugar, cream cheese and butter on medium speed for 3-4 minutes, until fluffy.  Beat in the eggs, one at a time, and the extract.  In a separate bowl, combine the flour, salt, baking powder, baking soda and orange zest.  Add the flour mixture to the mixing bowl in 3 additions, alternating with the milk, starting and ending with the flour, stirring just until moistened.

Divide batter equally between 6 bowls; I scooped a whole cup of batter into each bowl, and then just had a little left to divide evenly.  Use the food coloring to color each bowl of batter to the desired shades; be generous with the coloring so that the colors are saturated and vibrant, not pastel.

Pour batter into the pans (each color in a separate pan).  Bake cakes for 15-16 minutes, until a toothpick inserted in the center comes out clean.  Cool completely on a wire rack, covered loosely with a clean kitchen towel.

Make the Buttercream:

In the bowl of your stand mixer fitted with the whisk attachment, beat the butter and orange zest until smooth.  In a separate bowl, combine the powdered sugar and meringue powder.  With the mixer on low, add by spoonfuls.  Add the milk and increase speed to medium high, whipping until very light and fluffy, about 4-5 minutes.   Throughout the beating, taste and add orange extract if it needs additional orange flavor.  Scrape the bowl as needed.


Decide what order you want the colors of the cake layers to be.  I stacked mine in traditional rainbow color order - red, orange, yellow, green, blue and purple – from top to bottom, so I started with purple as the bottom layer.

Place the first layer of cake on a serving pedestal or cake board.  Spread with a thin layer of the buttercream.  Repeat with the rest of the cake layers, then frost the whole cake in a thin crumb coat of buttercream.  Let set in the fridge for 20-30 minutes before frosting with the final layer of buttercream and/or ruffles.  Garnish with sprinkles.

Recipe from Curly Girl Kitchen