Peanut Butter Marshmallow Fluffernutter Cupcakes

It's National Peanut Butter Lover's Day! One of my favorite combinations are peanut butter and marshmallow, so I had to make some fluffernutter cupcakes to celebrate. The fluffy, buttery vanilla cupcake, stuffed with marshmallow fluff, is the perfect base for this creamy peanut butter frosting. Like a dessert version of a fluffernutter sandwich, YUM!

Fluffernutter Cupcakes

Yield: 13 cupcakes



  • 1 1/4 cup (140g) cake flour, weighed or spooned and leveled
  • 3/4 cup (144g) granulated white sugar 
  • 3/4 teaspoon baking powder 
  • 1/4 teaspoon baking soda 
  • 1/4 teaspoon salt 
  • 1/4 cup (1/2 stick/57g) unsalted butter, softened 
  • 3 tablespoons vegetable oil 
  • 1 large egg, room temperature 
  • 1 large egg yolk, room temperature 
  • 2 teaspoons pure vanilla extract
  • 1/2 cup (120g) sour cream, room temperature 

Marshmallow Filling:
  • 1 jar marshmallow fluff/creme

Peanut Butter Frosting:
  • 1 cup peanut butter
  • 1/3 cup butter, softened 
  • 1 teaspoon vanilla extract
  • 1 1/2-2 cups powdered sugar, sifted
  • 1/3-1/2 cup heavy cream

  • Mini marshmallows and/or chopped peanuts (optional)


Prepare Cupcakes:
Preheat oven to 350° F (175° C). Line a cupcake pan with baking cups.

In a medium bowl or bowl of a stand mixer, mix together cake flour, sugar, baking powder, baking soda, and salt on low speed for about 20 seconds. Add butter and oil and mix for about 1-2 minutes to coat the flour, until mixture resembles wet sand.

In a small bowl, whisk together egg, yolk, vanilla, and sour cream until smooth. Slowly add the wet mixture on low speed. Increase to medium speed and beat for about 1 minute until batter is smooth.

Fill cupcake liners just over 1/2 full, about 3 tablespoons of batter per cup. Bake for 16-19 minutes, or until an inserted toothpick comes out clean. (For mini cupcakes, fill with about 1 1/2 tablespoons batter each and bake for about 8-10 minutes). Transfer to a wire rack to cool completely before frosting.

Prepare frosting: 
Beat peanut butter and butter on medium speed with an electric mixer, until creamy. Add vanilla. Beat in powdered sugar until incorporated. Slowly add the cream and beat on high speed until light and smooth.

Fill your cupcakes with marshmallow cream/fluff (see video below, or click here for a variety of techniques for filling a cupcake). Frost your cupcakes and top with a mini marshmallow and/or a sprinkling of chopped peanuts if desired.

To learn some tricks on how to fill your cupcakes, watch the video below or click here to view it on YouTube