This Post May Contain Affiliate Links. Please Read Our Disclosure Policy.
If you grew up on this classic sandwich of peanut butter and fluff you are going to love these peanut buttter cupcakes with marshmallow frosting and so will everyone who knows you! Peanut butter cupcakes filled with a peanut butter mousse and topped with a toasted marshmallow meringue frosting!
So growing up, one of my favorite go to sandwiches was a fluffernutter. So perhaps it should have been a no brainer that I ended up moving as an adult to where fluff was born.
I think it was fate.
I think it was also fate that I make this cupcake. My inner child did a serious happy dance when I bit into this cupcake.
So let’s talk more about the recipe, so you can get to making it ASAP.
How To Make Fluffernutter Cupcakes
First let’s start with the cupcake. A peanut butter cupcake. I started with my go to vanilla cupcake recipe and added peanut butter to the batter.
Pro Tip: Just be sure not to use natural peanut butter because it may incorporate too much oil into the batter.
Start by whisking together your dry ingredients- cake flour, baking powder, and salt.
Then cream your butter to lighten and have it increase in volume for 3 minutes. You need to use softened room temperature butter in order to properly aerate the mixture. Here are 3 ways to soften your butter quickly.
Once the butter has been creamed, add in your 2 cups of sugar a 1/4 cup of sugar at a time.
Then add in your eggs one at a time and mix until incorporated. Make sure the eggs are room temperature. To do this quickly, add your eggs to a bowl of warm water for 10 minutes.
Pro Tip: Give your eggs a light whisk before adding to the mixer bowl to prevent the mixture from curdling.
Then stir in the peanut butter. And in a seperate small bowl, combine the buttermilk and vanilla.
You will add the buttermilk and dry ingredients alternately beginning and ending with the dry ingredients.
Then scoop your cupcake batter into the liners. Be sure to fill 2/3 to 3/4 full to leave room for expansion and so the cupcakes don’t sink after baking. Overfilled cupcakes are one reason why cupcakes sink in the middle.
I thought this cupcake could use a little extra peanut butter, so I decided to make a peanut butter filling. This filling is no bake, and totally rocks. It’s so creamy and delicious. If you are new to adding a filling to a cupcake, then read my post on 4 ways to core a cupcake. Two of my favorite tools to fill a cupcake is probably the melon baller or apple corer.
How to make marshmallow frosting
Now for the toasted meringue frosting. This frosting is easier than it looks. This frosting comes together in 7 minutes. So guess what the name is. Yup, 7 minute frosting. It’s similar to making my marshmallow fluff.
I used this frosting for my lemon meringue pie cupcakes as well.
First start by heating your egg whites, sugar, water and corn syrup in a heatproof bowl over a pot of simmering water. I use my stand mixer bowl for this step.
You need to whisk this mixture now for 6-7 minutes. I like using my stick blender for this step and save myself the intense arm workout. You could also use a hand mixer for this step as well. After about 7 minutes, you will take it off the heat, add in your vanilla extract then beat on high for additional for another 1-2 minutes until stiff peaks form.
So now once your cupcakes are cooled, filled, and the frosting is made time to pipe the frosting. I used my French star tip for these cupcakes. And now for the super fun part! Toasting the frosting! I recently purchased my new kitchen torch and I am loving it! It’s so much fun to use!
If you don’t have a kitchen torch you can put your cupcakes in the oven on a cookie sheet, and set the oven to broil. But be careful! Don’t walk away! Your cupcakes will go from toasted to burnt to on fire before you know it!
- Make sure to measure your flour correctly by scooping and leveling. Here is a tutorial on how to measure your flour correctly.
- 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.
- Make sure your eggs, buttermilk, and butter are at room temperature.
- 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
Cold eggs are easier to separate. Separate your eggs, and then let the egg whites come to room temperature. Room temperature egg whites will increase in volume better than cold egg whites.
These cupcakes are best enjoyed the day of, but can be stored at room temperature for up to 2 days, be sure to keep covered.
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.
More Recipes To Try
Peanut butter cupcakes with marshmallow frosting
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
- 1¼ 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
- 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.