Did you know August 30th is National Toasted Marshmallow Day? If you’re looking for a fun new way to celebrate this delicious holiday with your family, you won’t want to miss my marshmallow cream filled rainbow cupcakes.
These colorful cupcakes are filled with marshmallow fluff and topped with sweet marshmallow frosting too.

Marshmallow Cream-filled Rainbow Cupcakes Recipe
Making these tasty treats together is a great way to spend quality time making memories in the kitchen. The recipe is easy enough to get the kids involved. Plus, these marshmallow cream filled cupcakes look fancy enough to wow your dinner guests too.
Want the recipe? Keep reading for step-by-step instructions for this Marshmallow Day cupcake recipe.
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Ingredients for Marshmallow Fluff Filled Vanilla Cupcakes with Rainbow Swirl Marshmallow Frosting
This recipe is a showstopper because it includes a delicious homemade marshmallow cream fluff and a gorgeous rainbow swirl marshmallow frosting.
Ready to get started creating your own creamy delicious cupcakes?

Here’s what you’ll need:
Easy Vanilla Cupcake Ingredients
- 1 white cake mix
- vegetable oil
- 4 egg whites
Cupcake making supplies:
- Cupcake pan
- Cupcake liners
- Cupcake injector
Cupcake liners and cupcake injectors are available from Walmart and Amazon.
Marshmallow Fluff Ingredients
- salted butter
- powdered sugar
- ¼ cup half and half
- 1-2 teaspoons Lorann marshmallow flavoring
Marshmallow Frosting Ingredients
- salted butter
- vanilla extract
- powdered sugar
- ¼ cup half and half
- 1 cup marshmallow creme
- Food coloring: red, orange, yellow, green, blue, and purple
I like to use this food coloring set available from Amazon. You’ll also need these supplies for decorating your marshmallow cream filled rainbow cupcakes:
- 6 small piping bags
- 1 large piping bag
- 1 large star frosting tip.
- Saran wrap

How To Make Marshmallow Cream Filled Rainbow Cupcakes
Once you’ve gathered all the ingredients and supplies, you’re ready to get started. Follow these step-by-step instructions for 2 dozen deliciously creamy filled rainbow cupcakes you can enjoy for National Toasted Marshmallow Day, a family celebration, or just because.

Cupcake Directions
- Preheat oven to 350 degrees. Spray or line a standard muffin tin.
- Add cake mix to a large mixing bowl.
- Then, using a hand or stand mixer, mix in water, oil, and egg whites at medium speed until well incorporated.
- Add the batter into the muffin tin until each cavity is about 2/3 full.
- Bake for 18-20 minutes, or until a toothpick comes out clean. Allow cupcakes to cool completely before adding the marshmallow fluff filling.

Rainbow Cupcakes Recipe
Once the cupcakes are prepared and cooled, follow these instructions for creamy marshmallow fluff filling:
- In a medium mixing bowl, using a hand or stand mixer, cream the butter and beat until light and fluffy.
- Then, mix in the powdered sugar, half and half, and marshmallow flavoring until well incorporated.
- Using the bottom of a spoon or other utensil, poke a hole in the middle of each cupcake, about ¾ down. Add the marshmallow fluff filling to the cupcake injector. Then, carefully inject the cream filling into the middle of each cupcake.




Frosting Instructions
- In a large mixing bowl, using a hand or stand mixer, cream the butter, and beat until light and fluffy. Mix in the vanilla extract. Then, mix in the marshmallow cream until smooth and creamy.
- Slowly mix in the powdered sugar, 1 cup at a time, while adding a bit of the half and half or milk in between each cup. Continue to mix for 1 minute or until creamy.
- Evenly divide the frosting into 6 containers. Add in one of each color of the food coloring, 1-2 drops at a time to each container (red to one, orange to the next, etc.). Mix until the desired color is achieved.
- Add each color to its own small piping bag until you have 6 bags of frosting in a rainbow of colors.
- Then, tear off a sheet of plastic wrap about 18-22” long. Pipe a 1-2” wide strip of frosting up the plastic wrap. They should be about 12-15” long. Repeat until you have a strip for each color.
- Now, carefully roll the frosting, moving from side to side. Start with the red, so you have a log of rainbow frosting. Make sure it is nice and firm but don’t squeeze it, so they are mushed together! Next, twist the ends together.
- Snip one twisted end off and insert it into your large, prepared piping bag. (You may want to squeeze a bit of frosting onto some plastic wrap until you see the rainbow colors come out.) Then, begin frosting the cupcakes.





These Rainbow Cupcakes are the moistest and delicious rainbow cupcakes! Easy to make and a super special dessert for any occasion!

Enjoy your cupcakes and don’t forget to come back here and tell me what you liked best.
Rainbow Marshmallow Cupcakes

I can’t wait to read about how much your family enjoyed these sweet marshmallow-filled rainbow cupcakes as much as mine did!
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Rainbow Cupcakes Recipe

Marshmallow Cream Filled Vanilla Cupcakes
Marshmallow Cream Filled Vanilla Cupcakes
Ingredients
- 1 15.25- ounce white cake mix
- 1 ¼ cups water
- 1/3 cup vegetable oil
- 4 egg whites
- Cupcake Injector Get them at Walmart or on Amazon
- Marshmallow Fluff Ingredients
- 1/2 cup salted butter softened
- 2 cups powdered sugar
- ¼ cup half and half
- 1-2 teaspoons Lorann marshmallow flavoring
- Marshmallow Frosting Ingredients
- 3 sticks salted butter softened
- 2 teaspoons vanilla extract
- 6 cups powdered sugar
- ¼ cup half and half
- 1 cup marshmallow creme
- Red, orange, yellow, green, blue, and purple gel food coloring
- 6 small piping bags
- 1 large piping bag, 1 large star frosting tip. Saran wrap.
Instructions
- Preheat oven to 350 degrees. Spray or line a standard muffin tin.
- Add cake mix to a large mixing bowl. Using a hand or stand mixer, mix in your water, oil, and egg whites on medium until well incorporated.
- Add batter into the muffin tin until each is about 2/3 full. Bake for 18-20 minutes, or until a toothpick comes out clean. Allow to cool completely before adding the marshmallow fluff filling.
- Directions for Marshmallow Fluff Filling:
- In a medium mixing bowl, using a hand or stand mixer, cream the butter, and beat until light and fluffy. Mix in the powdered sugar, half and half and marshmallow flavoring until well incorporated.
- Using the bottom of a spoon or other utensil, poke a hole in the middle of each cupcake, about ¾ down. Add the marshmallow fluff filling to the cupcake injector. Carefully inject the filling into the middle of each cupcake.
- Directions for Frosting:
- In a large mixing bowl, using a hand or stand mixer, cream the butter, and beat until light and fluffy. Mix in the vanilla extract. Mix in the marshmallow cream until smooth and creamy
- Slowly mix in the powdered sugar, 1 cup at a time, while adding a bit of the half and half or milk in between each cup. Continue to mix for 1 minute or until creamy.
- Evenly divide the frosting into 6 containers. Add in one of each color of the food coloring, 1-2 drops at a time to each container (red to one, orange to the next, etc.). Mix until desired color is achieved.
- Add each color to its own small piping bag until you have 6 bags of frosting in a rainbow of colors. Tear off a sheet of plastic wrap about 18-22” long. Pipe a 1-2” wide strip of frosting up the plastic wrap. They should be about 12-15” long. Repeat until you have a strip for each color.
- Now you are carefully going to roll the frosting, moving from side to side, starting with the red, so you have a log of rainbow frosting. Make sure it is nice and firm but don’t squeeze it, so they are mushed together! Twist the ends together.
- Snip one twisted end off and insert into your large, prepared piping bag. You may want to squeeze a bit onto some plastic wrap until you see the rainbow colors come out before frosting the cupcakes. Frost your cupcakes and enjoy!
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