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fluffernutter cupcakes
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2 from 1 vote

Peanut butter cupcakes with marshmallow frosting

A peanut butter cupcake filled with a no bake peanut butter mousse filling and topped with a toasted marshmallow frosting!
Prep Time1 hr
Cook Time22 mins
Total Time1 hr 22 mins
Course: Dessert
Cuisine: cupcakes
Servings: 30 cupcakes


For The Cupcakes

  • 3 cups (360 g) cake flour
  • 1 Tablespoons baking powder
  • ½ teaspoon salt
  • 1 cup (2 sticks, 226 g) unsalted butter at room temperature
  • 2 cups (400 g) granulated sugar
  • 5 large eggs at room temperature
  • 1/2 cup (135 g) smooth peanut butter
  • cups (300 ml) buttermilk at room temperature
  • 2 Tablespoons vanilla extract

For the peanut butter filling

  • 1 cup (113 g) confectioner sugar
  • 4 ounces cream cheese softened
  • 1/2 cup (135 g) smooth peanut butter
  • 1 teaspoon vanilla extract
  • 1 Tablespoon milk

For the Marshmallow Frosting

  • 1 1/2 cup (300 g) granulated sugar
  • 1/3 cup (80 ml) cold water
  • 2 large egg whites
  • 1 Tablespoon corn syrup
  • 1/4 teaspoon cream of tartar
  • pinch of salt
  • 1 1/2 teaspoon vanilla


For the Cupcakes

  • Prep pans and oven. Preheat your oven to 350°F and prepare your cupcake pans with cupcake paper liners. Set aside.
  • Combine dry ingredients. In a medium mixing bowl, combine the cake flour, baking powder and salt. Whisk together and set aside.
  • Cream butter. Add the butter to the bowl of an electric mixer fitted with the paddle attachment. Beat on medium-high speed for 3 minutes, until light and creamy in color. Scrape down the sides of the bowl and beat for one more minute.
  • Add sugar. Add the sugar to the butter mixture, ¼ cup at a time, beating 1 minute after each addition.
  • Add eggs and peanut butter. Mix in the eggs one at a time until incorporated. Add in your peanut butter and mix to combine. Scrape down the sides of the bowl as needed.
  • Combine buttermilk and vanilla. Combine the buttermilk and the vanilla extract in a liquid measuring cup and whisk to combine.
  • Alternate dry ingredients with buttermilk. With the mixer on low speed, add the dry ingredients alternately with the buttermilk/vanilla mixture, 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.
  • Bake cupcakes. Divide the batter between the prepared paper liners, filling each about 2/3 of the way full. Bake 18-22 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.

For the peanut butter filling

  • Mix all ingredients together. In a stand mixer bowl, using your paddle attachment combine all ingredients and mix to combine. You can also do this with a hand mixer in a mixing bowl or by hand with a wooden spoon. Keep refrigerated until ready to use.
  • Core and fill cupcakes. Once your cupcakes are cooled, remove the center (you can use a knife, apple corer, or melon baller) and fill with about a tablespoon of the the peanut butter filling.

For the frosting

  • Mix all ingredients except vanilla. Combine the egg whites, sugar, water, corn syrup, cream of tartar and salt in a large stainless steel bowl or other heatproof bowl. Use an electric handheld mixer to beat the ingredients together until well combined.
  • Whip to soft peaks. Place the bowl over a saucepan of simmering water. Continue to beat on medium-low speed for 3 minutes. Turn the speed up to high and beat for 3-4 minutes or until soft peaks begin to form.
  • Add vanilla and whip longer. Remove from heat, add the vanilla extract, and continue beating on high until the frosting is thick and spreadable, about 1-2 minutes. Cool to room temperature and use immediately.
  • Frost cupcakes. Pipe onto your cupcakes with a piping bag and pastry tip (I used a French star tip) Then lightly torch the frosting with a kitchen torch. Alternately, you could place them in your oven (put them on a cookie sheet, and no closer than middle rack) and set to broil but keep a really close eye one them otherwise they will burn.


  • Storage: Keep covered up at room temperature for up to 2 days. 
  • Freezing: I would freeze the cupcakes unfrosted, as the frosting won't freeze well. Freeze cupcakes, wrapped well, for up to 3 months, then thaw at room temperature before frosting. 
  • Cake Flour: This recipe uses cake flour which helps to create a light and fluffy cupcake. If you use all purpose flour it will change the texture a bit. You can also make your own cake flour.
  • Buttermilk: The recipe calls for buttermilk. Do not substitute regular milk because it will alter the balance of the ingredients due to the acidity in the milk.  You can also make your own cake flour
  • Peanut butter: Do not use an all natural peanut butter, it contains too much oil.