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+ servings
slice of rainbow cake on white plate with fork

Rainbow Cake

Turn simple white cake mix into something magical for your next big event! This easy Rainbow Cake pairs perfectly with buttercream frosting.
Course Dessert
Cuisine American
Keyword cake recipe, rainbow cake
Prep Time 2 hours
Cook Time 15 minutes
Cooling time 1 hour
Total Time 3 hours 15 minutes
Servings 18 servings
Calories 505kcal


  • 8 inch cake pans


For the Cakes:

  • 32.50 oz boxed white cake mix two 16.25 oz. boxes (I used Betty Crocker Super Moist)
  • eggs, oil and water amount according to boxed intructions
  • gel food coloring in six colors

For the Frosting:

  • 1 cup butter softened
  • 4 teaspoons vanilla extract
  • 2 pounds powdered sugar
  • 4 tablespoons milk give or take a few tablespoons
  • rainbow sprinkles optional


Make the Rainbow Cakes:

  • Preheat oven to 350 degrees. Line 6 8-inch cake pans with parchment paper around the bottom and spray with nonstick cooking spray. Set aside.
  • In a large bowl, make two cake mixes according to package directions with eggs, oil and water. Divide batter into 6 even portions. You can do this by eye or weigh the batter out and divide it by 6. Using the gel food coloring, color each bowl of batter brightly to make a rainbow using red, orange, yellow, green, blue and purple.
  • Pour each colored batter into the prepared pans and bake 13-17 minutes. Cool completely before frosting cake.

Make the Frosting:

  • Measure out the butter, powdered sugar and vanilla into a large bowl or the bowl of a stand mixer. Using a hand or stand mixer, start to combine the butter into the powdered sugar. With the mixer on, slowly stream in your milk tablespoon by tablespoon until it starts to come together and look creamy. If it hasn’t come together, add another tablespoon, mix and wait it out. After about 2 or 3 tablespoons, your frosting should be thick enough to hold its shape, but light enough to have a butter knife or rubber scraper run through it with ease.
  • Starting with the red cake on the bottom, layer the cakes up with vanilla frosting in between starting with red and ending with purple. Using the remaining frosting, frost exterior of cake smoothly. (If you want to do a crumb coat and refrigerate first and then finish the cake off with another layer of frosting, feel free to do that.) Decorate with rainbow sprinkles and serve.


Calories: 505kcal | Carbohydrates: 97g | Protein: 3g | Fat: 12g | Saturated Fat: 8g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 3g | Trans Fat: 1g | Cholesterol: 27mg | Sodium: 491mg | Potassium: 45mg | Fiber: 1g | Sugar: 74g | Vitamin A: 321IU | Calcium: 133mg | Iron: 1mg