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rainbow cupcake with white frosting and sprinkles.
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5 from 2 votes

Rainbow Cupcakes Recipe

These are my favorite EASY Rainbow Cupcakes! Start with a box mix for the cupcake but make a homemade marshmallow buttercream frosting and FOUR different ideas for topping!
Prep Time30 minutes
Cook Time20 minutes
Total Time50 minutes
Course: Dessert
Cuisine: American
Servings: 12 cupcakes
Calories: 128kcal
Author: Dorothy Kern
Cost: $9


For the Rainbow Cupcakes

  • 1 15 ounce box white cake mix , prepared with eggs, oil, and water called for on the box
  • Food coloring (red, orange, yellow, green, blue, purple (gel food coloring works best for vibrant colors)

Marshmallow Buttercream

  • ½ cup (113g) unsalted butter softened
  • 1 7 ounce jar (198g) marshmallow creme
  • 1 ½ cups (170g) powdered sugar
  • 1 teaspoon vanilla
  • Pinch salt

For the Cupcake Toppers

  • 24 white chocolate Reese's Peanut Butter Cups or
  • 12 Airheads Extremes cut in half, or
  • rainbow sprinkles


Make the Cupcakes

  • Mix the cake batter according to the recipe or box directions. Line your muffin tins with cupcake liners.
  • Divide your batter evenly among six bowls. Add food coloring to each bowl, one for each color of the rainbow (red, orange, yellow, green, blue, purple). Stir to combine.
  • You are going to layer the cupcakes into the liners in a reverse rainbow, so the purple is on the bottom and the red is on the top. To make this easier to do, place each color in a separate quart-sized Ziploc bag. Seal the bag almost all the way, leaving about 1/2" open for air to escape. Snip off a tiny corner and place a small amount in each cupcake liner, starting with purple (use just enough to cover the bottom of the liner). Repeat with the remaining colors in this order: blue, green, yellow, orange, red.
  • Bake according to box directions. Let cool completely.

Make the frosting

  • Beat butter and marshmallow creme together until smooth, then mix in powdered sugar, vanilla and salt. Frost cupcakes as desired (I like using a 1M tip).

Topping the cupcakes

  • Leave plain with the frosting.
  • Add rainbow sprinkles.
  • Place an Airhead Extreme in a rainbow arch on top.
  • Place a white chocolate peanut butter cup on top, frost it with frosting and sprinkle with sprinkles (like it's a mini cupcake ton top).
  • Store cupcakes in refrigerator to set frosting (it's a bit fluffy and will collapse if it's not set).



  • For the cupcake base you’ll need a boxe of white cake mix. Normally cake mixes make about 18-24 cupcakes but with all of the coloring and transferring of dishes, these make about 12-14.
  • Storing: you can store the frosted cupcakes loosely covered until ready to eat. No need to chill them unless you've made them a day before.
  • Freezing: you can freeze the unfrosted cupcakes and the frosting separately. Let thaw before frosting.
  • TIP: use a ziplock bag when filling the cupcake pans! Add one color to each bowl and stir until the color is evenly distributed in the batter. To make it easy to create the cupcake layers, transfer each batter to its own Ziploc bag and snip off one corner so you can squeeze the batter through it.
  • Turn these into double the rainbow with my rainbow buttercream!


Serving: 1cupcake | Calories: 128kcal | Carbohydrates: 15g | Protein: 1g | Fat: 8g | Saturated Fat: 5g | Cholesterol: 20mg | Sodium: 2mg | Sugar: 15g | Vitamin A: 236IU | Calcium: 2mg