Rainbow Cupcakes

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These Rainbow Cupcakes are a fun cupcake perfect for any occasion! Made with six layers of colors with an easy vanilla cupcake topped with an easy marshmallow buttercream frosting! Easy treat for St. Patrick’s Day!

rainbow cupcake with frosting and sprinkles


 

Rainbow cupcakes. So colorful and fun.  With St. Patrick’s Day around the corner, I love finding creative, and fun recipes to celebrate. I mean I love my green food items – like these Thin Mint cupcakes or these Andes mint brownies, and you can’t go wrong with a good Guinness chocolate cake. But this time I went all in with the rainbow fun. 

These rainbow cupcakes start with my perfect vanilla buttermilk cupcake recipe and I topped with an easy marshmallow buttercream frosting.

You could of course use any type of frosting here – Swiss meringue buttercream would be delicious or my Italian meringue buttercream is another great choice. Of course you can’t go wrong with my cream cheese frosting!

The cupcake batter then gets divided into six bowls and turned into rainbow colors. The different bright colors are layered into the the muffin tin making for a fun rainbow cupcake perfect for any birthday party.

Now you can keep these cupcakes unadorned or dress them up with a few rainbow sprinkles or gold sprinkles. So if you’re looking for a fun treat for St. Patrick’s day or in just need of a little color in your week then these colorful Rainbow cupcakes are it!

As March roars in, it’s time for green treats, minty desserts, and a touch of Baileys’ and Guinness! Check out this roundup of over 15 must-make St. Patrickโ€™s Day Desserts for your celebration.

See Also:

rainbow cupcake with a bite taken out of it

Why I Love This Rainbow Cupcake Recipe

  • Easy colorful treat for St. Patrick’s Day!
  • Wonderful cupcake for birthday parties
  • Made with my fluffy cupcake recipe
  • Can make ahead and even freeze
rainbow cupcakes on red cupcake stands

Ingredients Needed

For the cupcakes

  • Cake flour– Cake flour will yield a fluffier cupcake than using all purpose flour. You can make your own homemade cake flour too if you need to! 
  • Baking powder
  • Salt
  • Unsalted butter – You want the butter softened to room temperature so it can be creamed with the sugar properly.
  • Granulated sugar
  • Eggs – Make sure your eggs are at room temperature. If you add them in cold it will seize up the butter and knock out all the air you incorporated during the creaming process.
  • Vanilla extract
  • Buttermilk – If you don’t have any buttermilk then try making your own homemade buttermilk!
  • Food coloring (purple, blue, green, yellow, orange, red) – I recommend using a gel food coloring so it doesn’t add too much extra liquid. I like to use Americolor or Wilton.

For the frosting

rainbow cupcake ingredients

How To Make These Rainbow Cupcakes

Prep oven and pans. Position rack in the center of your oven and preheat the oven to 350ยฐ F (180ยฐC). Line a cupcake pan with cupcake liners. Set aside.

Combine dry ingredients.  In a medium mixing bowl, combine the flour, baking powder and salt. Whisk together and set aside.

cupcake dry ingredients in a bowl

Cream butter and sugar Cream together the butter and sugar in a large bowl with an electric mixer. I like to use my stand mixer fitted with the paddle attachment or you can use a hand mixer. Beat on medium-high speed for 3 minutes, until light and fluffy in color. Scrape down the sides of the bowl.

butter and sugar creamed together in mixing bowl

Add eggs and vanilla. Mix in the eggs one at a time until incorporated. Scrape down the sides of the bowl after each addition. Add vanilla and beat to combine.

egg added to creamed butter and sugar

Alternate dry ingredients with buttermilk. With the mixer on low speed, add the dry ingredients alternately with the buttermilk, beginning and ending with the dry ingredients and mixing just until incorporated.

flour and buttermilk alternately added to cupcake batter

Scrape down the sides of the bowl and mix for 15 seconds longer.

vanilla cupcake batter in bowl

Color the batter. Divide the batter between six separate bowls.

six bowls of vanilla cupcake batter

Add a few drops of food coloring to each of the small bowls (I did purple, blue, green, yellow, orange, and red). 

six bowls of cupcake batter colored a different color

Assemble the cupcakes. Add a little bit of each colored batter into each cupcake well. I ordered them with purple on the bottom, then blue, green, yellow, orange and the finished with red on the top. To do this evenly, start with the purple batter and divide that evenly between the 12 wells and then repeat with the other colors.

four photos showing the rainbow cupcake batter being assembled

You may not be able to divide them evenly and it’s ok if some get swirled or if you have to remove some from one cupcake well to add to another. Trust me they will come out beautiful!

Bake cupcakes. Bake 18-20 minutes, or until a toothpick inserted in the center comes out clean. Allow to cool in the pans 5-10 minutes, then transfer to a cooling rack. Cool cupcakes completely before frosting.

baked rainbow cupcakes in pan

Make the frosting

In a mixing bowl with an electric mixer, combine the butter and confectioners sugar. Mix on low speed at first, then increase the speed to medium until combined. 

butter and powdered sugar beaten together in bowl

Add the marshmallow fluff to the mixture and beat until combined. Scraping down the bowl as needed. 

marshmallow fluff added to frosting

Add in your heavy cream, vanilla extract and salt, and mix on medium to high speed for 7-8 minutes until light and creamy. If not using immediately, store in a container in the refrigerator until ready to use, mix again until light and fluffy.

Use right away on cooled cupcakes. If not using right away, then store in a closed container in the refrigerator for up to 5 days. You will need to mix the frosting again when ready to use to bring it back to that light and fluffy texture.

marshmallow buttercream frosting in bowl

Frosting And Decorating The Rainbow Cupcakes

Once your cupcakes are cooled it’s time to frost the rainbow cupcakes! To get that high beautiful swirl on my cupcakes I use a large closed star tip and a pastry bag.

You could also use my Vanilla Buttercream Frosting <– so creamy, light, fluffy vanilla frosting ever. But hey why stop there? These cupcakes are a perfect blank canvas. 

marshmallow buttercream frosting piped onto rainbow cupcakes

If you want a less sweet frosting then try –> Swiss Meringue Buttercream Recipe or Italian Meringue Buttercream (+video!). Or mix it up with some flavor like –> Easy Chocolate Buttercream Frosting or Cake Batter Buttercream Frosting.

For decorating you can keep these fun rainbow cupcakes plain, but why not add a few sprinkles for fun? You can add a few gold sprinkles perfect for St. Patrick’s Day. And try adding a piece of rainbow candy using those sour candy belts on top!

rainbow cupcake with cupcake liner peeled away

Recipe Tips

  • Measure your flour correctly. This will ensure you get a light, fluffy cupcake and not a dense, dry one. Measuring by weight is best, but if measuring by volume then stir the flour first in the bag. Then spoon the flour into your cup and level it off. Do not pack it down into the cup as it can result in over-measuring.
  • Check that oven temperature. Not all ovens are calibrated correctly, so use an oven thermometer to make sure yours is running at the correct temperature.
  • Bake in the middle of your oven. You want to make sure that the cupcakes bake evenly. And it can help if your oven has hot spots, then to rotate your pans halfway through baking.
  • Use quality vanilla extract. These are vanilla cupcakes after all, so donโ€™t cheap out on the vanilla. Use pure vanilla extract for the best flavor.
  • Make sure your refrigerator ingredients are at room temperature. You cannot use cold butter, eggs, or buttermilk in this recipe or your cupcake batter will not be smooth and could affect how they rise in the end. Take your dairy ingredients out of the fridge about 30 minutes to 1 hour before.
  • Donโ€™t overfill your cupcakes. This could result in your cupcakes sinking in the middle after baking and ugly cupcake tops. Scoop about 2/3 full.
  • Check for doneness. You want to make sure to check with a toothpick to look for moist crumbs, and the tops should spring back to the touch.
  • Use gel food coloring. I prefer gel food coloring so you don’t have to add much to get vibrant colors. Too much of the liquid coloring can make your frosting runny.

Make This Recipe Your Own

  • Use gluten free flour. You can swap the flour for a 1:1 gluten free flour blend. I like GF Jules, but King Arthur Flour or Bob’s Red Mill also works.
  • Make dairy free. Use a vegan butter in the cupcakes and for the frosting. And use a dairy-free milk.
  • Color the frosting too! Make swirls of rainbow frosting on top instead of just leaving the frosting white. You can check out how make swirled frosting here. 
  • Use a white cake recipe. Instead of my vanilla buttermilk cupcakes, you can use this white cake recipe and make cupcakes with them instead (way better than white cake mix out there!)
rainbow cupcake with bite missing and tipped over on its side

Storage FAQs

Can I make these cupcakes ahead of time?

You can store these cupcake frosted in the fridge for up to 3 days, or unfrosted covered overnight in an airtight container. But when serving, if refrigerated with frosting, make sure to bring to room temperature as the frosting can harden and it’s like eating a stick of butter! ย 

Can I freeze these rainbow cupcakes?

Yes these cupcakes freeze wonderfully. You can freeze frosted cupcakes or unfrosted cupcakes, for up to 3 months. I like to freeze cupcake solid then wrap each cupcake in plastic wrap and store in a freezer bag. Check out my post on how toย freeze cupcakes.ย 

Can I use all purpose flour?

Yes you can but the cupcakes might not be as fluffy.

Can I use liquid food coloring?

Yes you can but the cupcake batter might be a bit more liquidy.

Can I use natural food coloring?

Yes you can but the colors won’t be as vibrant.

rainbow cupcakes on a plate

More Recipes To Try

rainbow cupcake with frosting and sprinkles

Rainbow Cupcakes

Rainbow cupcakes perfect for St. Patrick's Day! Made with my easy vanilla buttermilk cupcakes and topped with a marshmallow buttercream frosting.
5 from 1 vote
Print Pin Rate
Course: Dessert
Cuisine: American
Prep Time: 30 minutes
Cook Time: 20 minutes
Total Time: 50 minutes
Servings: 12 cupcakes
Calories: 532kcal

Ingredients

For cupcakes

  • 1 1/4 cups (150 g) cake flour
  • 1 1/4 teaspoons baking powder
  • 1/2 teaspoon salt
  • 1/2 cup (1 stick, 113 g) unsalted butter at room temperature
  • 3/4 cup (150 g) granulated sugar
  • 2 large eggs at room temperature
  • 1 tablespoon pure vanilla extract
  • 1/2 cup (120 ml) buttermilk at room temperature
  • Food coloring orange, yellow, green, blue and purple gel food coloring

For marshmallow buttercream frosting

  • 1 1/4 cups (2 1/2 sticks, 283 g) unsalted butter softened
  • 2 1/2 cups (283 g) powdered sugar
  • 7 ounces marshmallow fluff
  • 2 Tablespoons heavy cream
  • 2 teaspoons pure vanilla extract
  • Pinch of salt

Instructions

Make cupcakes.

  • Prep oven and pans.ย Position rack in the center of your oven and preheat the oven to 350ยฐ F (180ยฐC).ย Line aย cupcake panย with paper liners. Set aside.
  • Combine dry ingredients.ย ย In a medium mixing bowl, combine the cake flour, baking powder and salt. Whisk together and set aside. 1 1/4 cups (150 g) cake flour 1 1/4 teaspoons baking powder 1/2 teaspoon salt
  • Cream butter and sugarย Cream together the butter and sugar to the bowl of an electric mixer fitted with the paddle attachment. Beat on medium-high speed for 3 minutes, until light and fluffy in color. Scrape down the sides of the bowl. 1/2 cup (1 stick, 113 g) unsalted butter 3/4 cup (150 g) granulated sugar
  • Add eggs and vanilla.ย Mix in the eggs one at a time until incorporated. Scrape down the sides of the bowl after each addition.ย Add vanilla and beat to combine. 2 large eggs 1 tablespoon pure vanilla extract
  • Alternate dry ingredients with buttermilk.ย With the mixer on low speed, add the dry ingredients alternately with the buttermilk, beginning and ending with the dry ingredients and mixing just until incorporated. Scrape down the sides of the bowl and mix for 15 seconds longer. 1/2 cup (120 ml) buttermilk
  • Color the cupcake batter. Divide the cupcake batter between six bowls. Add a few drops of food coloring to each bowl. I used purple, blue, green, orange, yellow and red.
  • Divide cupcake batter. Divide the batter between the prepared paper liners. Add a small spoonful of each color to each cupcake well. I started with purple, then blue, green, yellow orange then red.
  • Bake cupcakes.ย Bake 18-20 minutes, or until a toothpick inserted in the center comes out clean. Allow to cool in the pans 5-10 minutes, then transfer to a cooling rack to cool completely before frosting.

Make frosting.

  • Mix butter and sugar. In a mixing bowl, beat together the butter and powdered sugar together until light and fluffy, about 2-3 minutes. 1 1/4 cups (2 1/2 sticks, 283 g) unsalted butter 2 1/2 cups (283 g) powdered sugar
  • Add fluff. Add the marshmallow fluff to the mixture and beat until combined. Scraping down the bowl as needed. 7 ounces marshmallow fluff
  • Add heavy cream, vanilla, and salt. Add heavy cream, vanilla, and salt. Add in your heavy cream, vanilla extract and salt, and mix on medium to high speed for 7-8 minutes until light and creamy. If not using immediately, store in a container in the refrigerator until ready to use, mix again until light and fluffy. 2 Tablespoons heavy cream 2 teaspoons pure vanilla extract Pinch of salt

Frost cupcakes. With a large piping tip fitted into a large piping bag, pipe frosting onto cupcakes. Top with sprinkles if desired!

    Notes

    • Storage: You can store these cupcake frosted in the fridge for up to 3 days, or unfrosted covered overnight in an airtight container. But when serving, if refrigerated with frosting, make sure to bring to room temperature as the frosting can harden and it’s like eating a stick of butter!ย 
    • Freezing: Yes these cupcakes freeze wonderfully. You can freeze frosted cupcakes or unfrosted cupcakes, for up to 3 months. I like to freeze cupcake solid then wrap each cupcake in plastic wrap and store in a freezer bag. Check out my post on how to freeze cupcakes.ย 
    • Cake flour: You can make your own cake flour or use all purpose flour (cupcakes might not turn out as fluffy).ย 
    • Buttermilk: If you don’t have any, make your own buttermilk (add 1 1/2 teaspoons lemon juice or vinegar to 1/2 cup milk stir and let sit for 5 minutes before using.

    Nutrition

    Calories: 532kcal | Carbohydrates: 66g | Protein: 4g | Fat: 29g | Saturated Fat: 18g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 8g | Trans Fat: 1g | Cholesterol: 106mg | Sodium: 125mg | Potassium: 99mg | Fiber: 0.4g | Sugar: 48g | Vitamin A: 926IU | Vitamin C: 0.01mg | Calcium: 47mg | Iron: 0.4mg
    Tried this Recipe? Pin it for Later!Mention @BostonGirlBakes or tag #BostonGirlBakes!


     

    9 Comments

    1. J at BlessHerHeartYall.com says:

      What a great idea for St. Patrick’s Day and for birthdays and other celebrations! So much fun in these little treats!

      1. Heather | Boston Girl Bakes says:

        Thank you! These were so much fun to admire …and also eat obviously ๐Ÿ™‚

      1. Heather | Boston Girl Bakes says:

        Thank you Bintu! And that’s a great idea I was thinking St. Patrick’s Day but you’re right these could be enjoyed all year long for a kid’s birthday party!

    2. Michelle Blackwood says:

      I have meaning to make rainbow cupcakes, I really love how yours are so simple and pretty!

      1. Heather | Boston Girl Bakes says:

        Thanks Michelle! They are just so cute when they come out of the pans you can’t help but smile at them!

    3. What a fun idea…my kids would go nuts for this cupcakes! These are adorable and sound scrumptious! Pinned.

      1. Heather | Boston Girl Bakes says:

        Thank you! And thanks for pinning them..hope your kids love them ๐Ÿ™‚

    5 from 1 vote (1 rating without comment)

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