For A Girl in LA’s one year anniversary, I wanted to do something special to commemorate the milestone. I decided to create a rainbow sprinkle cake from scratch using a recipe inspired from Delish.com. This was the first time I baked a cake from the ground up and I was quite surprised at how easy (and how much fun) it was. I mean, who doesn’t love a vanilla / buttercream cake covered in sprinkles and glitter?
Most the the ingredients I used were bought at my local grocery store. I did buy a few things on Amazon like the unicorn glitter confetti, the pink glitter dust, and the cake decorating kit. When it came to decorating it I watched a tutorial on how to get the sprinkles on there without creating a mess which you can also find at the bottom of this post.
For The Cake:
- 6 egg whites
- 1 c. sugar
- 1 c. unsalted butter
- 3 tbsp. applesauce
- 2 tsp. pure vanilla extract
- 2 whole eggs
- 2¼ c. cake flour
- 2 tsp. baking powder
- pinch of salt
- 4 different hues of food coloring
- 2 c. Buttercream Frosting (below)
- 1 c. unsalted butter
- 3 c. confectioners’ sugar
- 1 cup heavy cream
- 1 tbsp. pure vanilla extract
- About 1 cup sprinkles (rainbow, stars, nonpareils, and glitter)
Make The Cake:
Preheat oven to 350 degrees F. Line 4 6-inch cake pans with parchment paper, butter and flour so it doesn’t stick.
Beat egg whites with an electric mixer on medium-high speed until foamy, about 2 minutes. Increase mixer speed to high and continue beating until soft peaks form, about 3 minutes. Gradually add ½ cup of the sugar, continuing to beat until stiff peaks form, about 3 minutes more.
In another large mixing bowl, cream butter, the remaining ½ cup of sugar, applesauce, and vanilla on medium speed until light and fluffy, about 5 minutes. Add the eggs and mix on medium speed for 1 more minute.
Sift together flour, baking powder, and salt. Add to butter mixture and mix on medium speed for 1 minute. Pour in ¾ cup water and mix to combine. Fold in egg whites with a large spatula.
Divide batter evenly among 4 small bowls. Starting with the lightest color, tint batter with food coloring, whisking in a few drops at a time until the desired intensity is reached. Pour each of the colored batters into a different parchment-lined cake pan (each should be half full) and bake until a toothpick inserted in the center comes out clean, about 12 to 15 minutes.
Make the Buttercream Frosting:
With an electric mixer on medium-high speed, add butter, confectioners’ sugar, ½ cup at a time, add ¼ cup of heavy cream, at a time. Beat until smooth.
Scrape down the sides of the bowl with a rubber spatula. Add vanilla and beat for 1 minute more, or until soft and fluffy. Use immediately or refrigerate, covered, for up to 5 days.
Assembling the Cake: Stack layers according to the colors of the rainbow, spreading a thin layer buttercream between each. Using an offset spatula, frost the whole cake with a thin layer of buttercream.
Place cake on a freezer-safe plate. Freeze for 15 minutes, or until buttercream is firm. Remove from freezer and cover cake in sprinkles. (To learn how to decorate the cake, watch this tutorial.)
- Make sure you clean the frosting from the side of your cake plate so that the sprinkles won’t stick.
- Using your hands, start at the bottom and work your way up.