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These adorable Rainbow Cupcakes never fail to please! They start with cake mix so they’re super easy with layers of vibrant colors and homemade marshmallow frosting. Plus, I’m showing you how to top a rainbow cupcake four different ways.

rainbow cupcake with bite missing


Best Easy Rainbow Cupcakes

I am IN LOVE WITH RAINBOWS! I have been for years, even before they became so popular in recent years. Around my 35th birthday I declared that my 40th would be a rainbow party – and it was! My office is even decorated with unicorns, rainbows and, of course, lots of sprinkles! I have been making this rainbow cupcake recipe for years and they always bring a smile to everyone’s faces.

Starts with a cake mix so it’s way easier than from scratch – but we’re making a from scratch Marshmallow Buttercream so no one will know. The frosting is the best part of the cupcakes – other than how pretty they are! PLUS I’m showing four different ways to decorate these cupcakes! These beautiful cupcakes are perfect for birthday parties or St. Patrick’s Day or Pride Month – the inside is tie dye and gorgeous!

rainbow cupcake with white frosting and sprinkles.

Ingredients Needed

  • White Cake Mix – it’s important to use white cake so your colors turn out properly.
  • Food Coloring – I prefer gel food coloring because the colors are more vibrant without watering down the batter.
  • Marshmallow Cream – Also called marshmallow creme or fluff, this is added to my vanilla buttercream for a fluffy sweet cloud-like frosting on top.

Be sure to see the recipe card below for full ingredients & instructions!

How to Make Rainbow Cupcakes

  • Just mix up the cupcake batter in a medium bowl following the instructions on the package.
  • Once it’s made, divide the color batter evenly among six bowls.
  • Once your batter is divided it’s time to create the colors. I like to use gel food coloring (I love Americolor brand) because the colors always turn out extra bright and pretty. For the gel coloring, you’ll need red, orange, yellow, green, blue, and purple.
  • To create a rainbow, you will want to layer the colors in this order: Purple, Blue, Green, Yellow, Orange, and Red on top.
  • Bake the cupcakes in a preheated oven until a toothpick comes out clean from the center. Cool them completely before you decorate them.

Homemade Marshmallow Frosting

Once your cupcakes are cooled, they are ready for decorating. You could use vanilla buttercream or cream cheese frosting but I love marshmallow frosting for these because it looks like a cloud.

Cream room temperature butter with the marshmallow crème in a large bowl using an electric mixer or hand mixer. Add pure vanilla extract and a pinch of salt and powdered sugar and beat together. Transfer the frosting to a piping bag and pipe the it onto each cupcake so it looks like a puffy white cloud.

rainbow cupcake with white frosting and rainbow fruit rope on top.

Rainbow Cupcake Toppers

What I love about these cupcakes is that there are several different ways to decorate them. These are my favorite rainbow cupcake toppers, but feel free to experiment!

  1. Plain: For a simple decoration just top them with the marshmallow frosting – totally cute that way!
  2. Sprinkles: Or, add some rainbow sprinkles to dress them up a little. So easy.
  3. Rainbows: You can also top the frosting with an Airhead Extreme which is a chewy candy rainbow. Just lightly press one end into the surface of the cupcake, bend it into an arch and secure the other end in the cupcake so it looks like a little rainbow.
  4. Mini cupcakes: You can create a mini “cupcake” decoration by topping the frosting with a mini white chocolate peanut butter cup. Add a dollop of frosting on top with some sprinkles.
rainbow cupcake with white frosting and white Reese's on top

Expert Tips

  • 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. Place both in an airtight container. 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!

FAQs

Do I need to grease the liners for cupcakes?

No you don’t need to grease the cupcake liners for these.

How long do cupcakes take to bake?

Follow the directions for baking on the box mix. Make sure not to over bake them so the red layer stays red.

What is the best icing for rainbow cupcakes?

Something fluffy and white, which is why I love the marshmallow frosting!

rainbow cupcake with white frosting and sprinkles.

Rainbow Cupcakes Recipe

5 from 6 votes
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 Time 30 minutes
Cook Time 20 minutes
Total Time 50 minutes
Yield 12 cupcakes
Serving Size 1 cupcake

Ingredients
 

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
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Instructions

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).

Recipe Video

Recipe Notes

  • 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!

Recipe Nutrition

Serving: 1cupcake | Calories: 128kcal | Carbohydrates: 15g | Protein: 1g | Fat: 8g | Saturated Fat: 5g | Cholesterol: 20mg | Sodium: 2mg | Sugar: 15g | Vitamin A: 236IU | Calcium: 2mg
Nutritional information not guaranteed to be accurate
Course Dessert
Cuisine American

Favorite Rainbow Desserts



Dorothy Kern

Welcome to Crazy for Crust, where I share recipes that are sometimes crazy, often with a crust, and always served with a slice of life.

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14 Comments

  1. My family loved it, my nephew had 3 cupcakes in one day!! Everybody loved them they wanted more cupcakes.

  2. Dorothy,
    Love the toppers! So cute! 🙂 I’ve made these cupcakes for a few years and love them! 🙂
    Mackenzie

  3. These are too fun. I’m such a cupcake girl…and topping one with another just makes me smile. 🙂

  4. What a fun idea! And I agree, they grow up too fast (and not fast enough, sometimes…). My older daughter is going to be six in about two months, and I’m having a hard time coming to terms with that!