Rainbow Surprise Cake Recipe

A birthday party simply isn’t complete without the perfect birthday cake, but if you’re a Pinterest-perfectionist like me, this may seem out of reach. When I started researching ideas for our birthday issue, I stumbled across explosion-cake perfection—cue the flood of sprinkles—and I just had to give it a try. If you’ve been searching for a way to elevate your child’s standard birthday cake, look no further. This rainbow surprise cake is surprisingly easy to make; I used store-bought cake mix and frosting to assemble this beauty in just a couple hours. It’s just as tasty as it is pretty, and when it’s time to cut into the cake, don’t be surprised if your little partygoers squeal with glee.

Rainbow Surprise Cake

Supplies:

1 store-bought white cake mix
6-inch round cake pans (I used a set of 5 pans, but you can reuse the pans if you only have 1 or 2)
Cooking spray
2 batches of your favorite buttercream frosting (or about 2 pounds store-bought frosting)
Food coloring (I used red, yellow, green, and blue, and mixed red and blue to make purple. You can customize the colors to match the party theme.
Round cookie cutter or small glass (I used a 2-inch-diameter shot glass)
About 1 cup mixed sprinkles and/or candy-coated chocolate for filling and decoration (2-3 varieties)
Spatula for frosting

Bake the cake:

Preheat oven to about 25 degrees less than called for on the box directions. Spray the pans with cooking spray.
Mix the cake batter and divide evenly into 5 small bowls (approximately ½ cup in each). Add food coloring to each bowl and mix until desired color is reached. Pour into the greased cake pans, filling each pan about halfway.
Bake the cakes for about 20-25 minutes or until golden and firm. Let cake layers cool in pans completely before removing. Chill layers in the fridge for a few hours or overnight.

Assemble the cake:

Place 1 cake layer on your serving plate and frost the top. Use a round cookie cutter or small glass to cut a hole in the middle of 3 of the other layers, leaving the last layer whole.
Place one of the cut layers on top of the frosted bottom layer; frost the top. Repeat with 2 remaining cut layers. (This will create a well down the center of the cake.)
Once the first 4 layers are assembled, mix together sprinkles and candy in a small bowl and pour inside the well in the cake.
Add the top layer and chill the assembled cake in the fridge for 20-30 minutes before frosting.
Once chilled, remove the cake from the fridge and apply a thin crumb coat to the outside of the cake. Return to the fridge for another 20-30 minutes.
Add a final layer of frosting to the outside of the cake, and chill for another 15-20 minutes. Once the frosting is set, remove the cake from the fridge and decorate with sprinkles and decorations of your choice. Chill the finished cake until you’re ready to serve.