Make cupcakes with rainbow frosting and marshmallow clouds for a St. Patrick’s Day or Birthday treat. These turn out so cute with the rainbow of vibrant color.

More St. Patrick’s Day Ideas: St. Patrick’s Day Charades Printable Cards, Leprechaun Bars and Lucky Treat Bags.

Rainbow cupcakes with fluffy buttercream frosting are a delightful treat that will bring a burst of color and joy to any occasion. These cupcakes are not only visually appealing but also incredibly delicious. The combination of moist vanilla cupcakes and vibrant rainbow frosting is sure to impress both kids and adults alike. Whether you’re hosting a birthday party, a baby shower, or simply craving a sweet treat, these cupcakes are the perfect choice.

Table of Contents

Why You’ll Love This Recipe:

Here are a couple reasons why you will adore these sweet rainbow frosting cupcakes:

Visual Delight: The vibrant rainbow frosting on top of these cupcakes is a feast for the eyes. The beautiful colors will instantly brighten up any dessert table and make your cupcakes stand out.

Moist and Fluffy: The vanilla cupcakes are incredibly moist and fluffy, thanks to the perfect balance of ingredients. Each bite is a heavenly experience that will leave you craving for more.

Ingredients:

First things first. You will need the following ingredients to produce the best results for this vanilla rainbow cupcake recipe.

For the cupcakes:

½ cup unsalted butter, softened
1 ⅔ cups sugar
6 egg whites
1 teaspoon vanilla extract
¼ cup oil
1 ¼ cups milk
½ teaspoon salt
2 ½ teaspoons baking powder
2 cups flour

For the frosting:

1 cup unsalted butter, softened
1 teaspoon vanilla
1 teaspoon salt
4 cups powdered sugar
3 tablespoons milk
Food coloring (purple, blue, pink, orange, yellow, green) to make the rainbow buttercream frosting
Mini marshmallows (to decorate)

How to Make the Recipe:

For the Cupcakes:

I love this recipe for plain vanilla cupcakes. It is a great base for the best cupcakes.

The first step is to preheat the oven to 350 degrees. Prepare your muffin pan(s) with cupcake liners and set aside.
In the bowl of a stand mixer, cream together the softened butter and sugar until smooth.
Add in the egg whites, oil, and vanilla. Mix well.
Pour in the milk and mix to combine. Don’t worry if the mixture appears curdled; this is normal.
Add the salt, baking powder, and flour. Mix well, scraping down the sides of the bowl if needed.
Measure out the batter and fill each muffin cavity until about ½-⅔ full.
Bake in the preheated oven for approximately 14-16 minutes or until the cupcakes are golden brown and the center of the cupcake iis set.
Allow the cupcakes to cool completely before decorating with swirls of rainbow frosting.

For the buttercream frosting:

I love this frosting recipe, it is one of my favorite frostings for birthday cakes, funfetti cupcakes and even this chocolate cupcake recipe.

In the bowl of a stand mixer or using a large bowl and hand mixer, combine the butter, vanilla, salt, and half of the powdered sugar. Mix on low speed until combined.
Add in the remaining powdered sugar and the milk. Mix on low speed until combined.
Increase the speed to medium and mix for an additional minute until the frosting is fluffy and smooth.
Divide the frosting into equal portions for each color. Transfer each portion to individual piping bags.
Line out a piece of plastic wrap approximately 18-24 inches long. Pipe each color onto the plastic wrap in rainbow order – purple, blue, green, yellow, orange, and then pink.
Roll the plastic wrap and colored frosting together, creating a log. Place the log of frosting into a piping/pastry bag fitted with a large star tip.

To decorate:

Use these frosting tips for how to decorate these cupcakes using the basic buttercream frosting in bright colors to make rainbows.

Once the cupcakes are cool, pipe a small mound of white frosting onto each cupcake.
Use a butter knife or offset spatula to spread and flatten the frosting to the edges.
Use the colored frosting bag to create an inverted “U” or horseshoe shape on top of the white frosting. Twist the piping bag mid-squeeze to show all the colors and add dimension.
Immediately place mini marshmallow “clouds” on top of the frosting before it crusts over.
The best part, show of and enjoy eating these yummy cupcakes.

Places to Take or Use This Recipe For:

St. Patrick’s Day Party: Celebrate on March 17th with cute rainbow cupcakes. Use green cupcake liners in the cupcake pan when baking for a touch of St. Patty’s green.

Birthday parties: These rainbow cupcakes will be the star of any birthday celebration, delighting both kids and adults.

Baby showers: Add a touch of whimsy to a baby shower with these colorful and delicious treats.

School events: Surprise your child’s classmates with these vibrant cupcakes for a school event or bake sale.

Potluck parties: Impress your friends and family with these eye-catching cupcakes at your next potluck gathering.

Rainbow Party: Any rainbow themed party needs to have these gorgeous cupcakes!

Variations for the Recipe:

Chocolate lovers: Add cocoa powder to the cupcake batter for a chocolate twist.

Lemon zest: Add lemon zest to the frosting for a refreshing citrus flavor.

Sprinkles: Decorate the cupcakes with colorful rainbow sprinkles for an extra festive touch.

Colorful cupcake batter: You can also add the gel colors to the cupcake batter after splitting the batter into six separate bowls and mixing each of the different colors. Then add a small amount of the colored batter to each cupcake liner.

Storage and Make-Ahead:

Cupcakes should be stored in an airtight container in the fridge for up to 3 days or frozen for 3 months. If making ahead, you can bake the cupcakes in advance and freeze them without frosting. Thaw them a little bit before decorating and serving.

Common Questions about Cupcakes with Rainbow Frosting:

How do I achieve vibrant colors in the frosting?

To achieve vibrant colors, use gel food coloring instead of liquid food coloring. Gel food coloring provides more intense and vibrant colors without altering the consistency of the frosting.

Can I use this recipe for a cake instead of cupcakes?

Yes, you can use this recipe to make a rainbow cake. Simply divide the batter evenly between three 8-inch round cake pans and adjust the baking time accordingly.

Can I use different flavors for the cupcakes?

Absolutely! You can experiment with different flavors by adding extracts such as almond, lemon, or coconut to the cupcake batter. Or make your own funfetti cake batter by adding in sprinkles to the vanilla cake recipe listed above.

Can I make the vanilla buttercream frosting ahead of time?

Yes, you can make the frosting ahead of time and store it in an airtight container in the fridge for up to a week. Before using, let it come to room temperature and give it a quick mix to restore its fluffy texture.

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Rainbow Cupcakes

Vanilla flavored cupcakes with rainbow frosting and marshmallow clouds.

Prep Time30

Cook Time16

Total Time46

Course: Dessert

Cuisine: American

Keyword: rainbow cupcakes, rainbow frosting, st patrick’s day cupcakes, vanilla buttercream, vanilla cupcakes

Servings: 24

Ingredients

For the cupcakes

½ c unsalted butter softened
1 ⅔ c sugar
6 egg whites
1 t vanilla
¼ c oil
1 ¼ c milk
½ t salt
2 ½ t baking powder
2 c flour

For the frosting

1 c unsalted butter softened
1 t vanilla
1 t salt
4 c powdered sugar
3 T milk
Food coloring – purple blue, pink, orange, yellow, green
Mini marshmallows – to decorate

Instructions

For the cupcakes

Preheat the oven to 350 degrees. Prep your muffin tin(s) with liners and set aside.
In the bowl of a stand mixer, combine the softened butter and sugar. Cream until smooth.
Add in the egg whites, oil and vanilla. Mix well.
Add the milk and mix to combine. The mixture may appear curdled – this is normal.
Add in the salt, baking powder and flour and mix well. Stop the machine, scrape down the sides and mix again.
Measure out the batter and fill each cavity until about ½-⅔ full. Bake in the preheated oven for approximately 14 minutes or until the cupcakes are golden brown and the center is set. Allow the cupcakes to cool completely before decorating.

For the frosting

In the bowl of a stand mixer, combine the butter, vanilla, salt and about half of the powdered sugar.
Mix on low speed until combined. Add in the remaining powdered sugar and the milk.
Mix on low speed until combined. Once combined, bump up the speed to medium for an additional minute until the frosting is fluffy and smooth.
Divide the frosting – measure out ½ of a cup for each of the colors. The remaining frosting will stay white and it can be transferred to a piping bag. Tint each of the colors and transfer that frosting to each individual bag.
Line out a strip of plastic wrap approximately 18-24 inches long. Pipe each color onto the plastic wrap in rainbow order – purple, blue, green, yellow, orange and then pink.
Roll the plastic wrap and coloring frosting so that they overlap. Place the log of frosting into a piping bag fitted with a large star tip.

To decorate

Once the cupcakes are cool, pipe a small mound of white frosting onto each cupcake. Use a butter knife or offset spatula to spread and flatten the frosting to the edges.
Use the colored frosting bag to create an inverted “U” or horseshoe shape. Twist the piping bag mid squeeze to show all the colors and add dimension.
Immediately place the mini marshmallow “clouds” before the frosting crusts over.

Notes

Storage: Cupcakes should be stored in an airtight container in the fridge for up to 3 days or frozen for 3 months.

These rainbow cupcakes with fluffy frosting are a delightful treat that will bring a smile to anyone’s face. With their vibrant colors and delicious taste, they are perfect for any occasion. Whether you’re hosting a party or simply want to indulge in a sweet treat, these cupcakes are sure to impress. So, gather your ingredients, follow the easy steps, and enjoy the magic of these colorful creations!

More St. Patrick’s Day Fun Ideas:

Please pin this post for later and follow along on Pinterest:

How to Make Perfect Cupcakes with Rainbow Frosting

Why You’ll Love This Recipe: