Rainbow Cupcakes

rainbow cupcake with a bite taken out of it

Light, buttery and moist rainbow cupcakes are six layers of color that bake up into a centerpiece-worthy treat. Top them off with fluffy white buttercream or tangy cream cheese frosting then complete your cupcake creations with a shower of rainbow sprinkles. There are so many cute rainbow candies, the decor options are endless!

Course Dessert

Cuisine American

Prep Time 20

Cook Time 15

Total Time 35

Servings cupcakes

Calories 524kcal

Author Elizabeth Marek

Equipment

2 cupcake pans
24 cupcake liners

Ingredients

Rainbow Cupcakes

1 box white cake mix I like Duncan Hines
1 cup all purpose flour
1 cup granulated sugar
¼ teaspoon salt
1 cup sour cream room temperature
½ cup unsalted butter melted
1 cup milk room temperature
3 large eggs room temperature
6 bottles gel food coloring: red, orange, yellow, green, blue, purple 2-3 tsps of each color

Easy Vanilla Buttercream

6 ounces pasteurized egg whites (from a box)
24 ounces powdered sugar
1 Tablespoon vanilla extract
½ teaspoon salt
24 ounces unsalted butter softened

US Customary - Metric

Instructions

Making Rainbow Cupcakes

Preheat the oven to 350° F and prepare 2 cupcake pans with paper cupcake liners.
Add the cake mix, flour, sugar, salt, sour cream, melted butter, eggs, and milk to the bowl of a stand mixer. You can also use a large bowl and a hand mixer.
Combine all of the dry ingredients and the wet ingredients on low speed and then mix on medium speed for 2 minutes.
Divide the batter into 6 separate bowls.
Using your preferred food color, color each of the small bowls in red, orange, yellow, green, blue, and purple to your desired shade of cake. The color will be more vibrant when baked. Pro-Tip: Make sure to use gel food coloring like ChefMaster or Americolor instead of liquid for more vibrant colors.
Starting with the purple batter, either pipe or spoon about 1-1.5 tablespoons of batter into each cupcake cup. Layer each colored batter on top of the last. Try to spread the batter to the edges so you can see the rainbow through the cupcake paper.
Place the cupcakes into the oven and bake for about 15 minutes. Make sure the center of the cupcake is done so it doesn’t sink when it cools.
Cool the cupcakes for 5 minutes in the pans, then remove and place them on a cooling rack to fully cool. This way the bottoms of the cupcake don't get wrinkly from the steam.

Easy Vanilla Buttercream

First, place the egg whites and the powdered sugar in a stand mixer bowl. Attach the whisk and combine the ingredients on low, and then whip them on high for 4 to 5 minutes (until shiny) to dissolve the powdered sugar.
Then, add in the salt and the vanilla extract.
Next, add in your softened butter piece-by-piece, and whip it with the whisk attachment for 8 to 10 minutes until white and fluffy. When it no longer tastes buttery, it's done!
Finally, switch to a paddle attachment and mix the buttercream on low speed for up to 15-20 minutes. This step is optional but if you want really creamy and bubble-free frosting, you don't want to skip it.

Assembling the Cupcakes

Prepare a pastry bag with easy buttercream and a large star tip. Pipe a swirl of vanilla buttercream frosting on top of each cupcake. Pro-tip: If you do not have a piping bag, you can use a Ziploc bag.
Cut the rainbow strip candy into 3-inch portions. Place the rainbow on top of the cupcake in an arch.
Add gold or rainbow sprinkles in any design you desire to the top of each cupcake.
To store the cupcakes, place them in an airtight container and store them at room temperature for up to 4 days. You can freeze unfrosted cupcakes or frosted cupcakes for up to a month.

Notes

For the best rise, fill your liners ⅔ with cupcake batter or 1 ½ ounces per cupcake
Make sure all your ingredients are at room temperature before mixing your batter (milk, butter, eggs).
Use clear vanilla extract for that “classic grocery store cake” flavor. Use good quality vanilla extract, vanilla bean paste, or even a vanilla bean for true vanilla flavor. One vanilla bean = 2 teaspoons vanilla extract.
Preheat your oven to 350ºF for 30 minutes before baking to give your cupcakes a good rise and set the dome.
Baked cupcakes can be frozen for up to 6 months.
If you don’t have a paddle attachment, mix by hand with a spatula to avoid overmixing.

Nutrition