Fluffernutter Brownies

Close up of fluffernutter brownie.

Bring a childhood favorite back in the form of rich, decadent brownies. These Fluffernutter Brownies are swirled with peanut butter and sweet marshmallow fluff to make the ultimate dessert.

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Two brownies stacked on top of each other with several behind them.

Think of the classic fluffernutter sandwich from childhood. Thick layers of peanut butter layered with marshmallow fluff. I took inspiration from the sandwich and added all those delightful flavors to my thick, fudgy brownie recipe.

And I’m so glad I did. If you need a rich, over the top dessert for your next gathering, these brownies are sure to be a winner with all their peanut butter, chocolate, marshmallowy goodness.

Close up of peanut butter and marshmallow swirl.

Fluffernutter Brownies Ingredients

Ready to make these incredible brownies? Here’s what you are going to need:

  • Butter
  • Cocoa powder: You can use dutch-processed or natural cocoa powder for this recipe.
  • Eggs
  • Vanilla extract
  • Sugar
  • Flour
  • Salt
  • Mini Unwrapped Reese’s Peanut Butter Cups
  • Peanut Butter
  • Marshmallow fluff
Close up of interior texture of peanut butter marshmallow brownies.

Make the One Bowl Brownie Batter

Heat a large pot or dutch oven over medium heat. Add the butter and allow it to melt. Add cocoa to the melted butter and whisk until smooth.

Remove from the heat source and whisk in the eggs, vanilla extract and sugar. Once smooth, stir in the dry ingredients.

Lastly, fold in the mini peanut butter cups and spread the brownie batter into a greased 9-inch baking pan.

Big pile of fluffernutter brownies.

Now to Swirl

Place the peanut butter in a microwave safe bowl and microwave for 20 seconds or until runny. Dollop randomly over the top of the brownie batter.

Repeat the same process with the marshmallow fluff. Take a toothpick or skewer and drag it randomly to create a pattern and cover the surface of the brownies.

Pile of fluffernutter bronwies.

Simple Shortcut for Fluffernutter Brownies

If you’re short on time or don’t feel like whipping up the homemade brownie batter (although it’s SUPER easy) you can use a boxed brownie mix instead. Make sure to use a great quality mix – Ghiradelli is my favorite.

Simply prepare the mix as stated on the box then mix in the mini peanut butter cups. Proceed with the recipe for the fluffernutter topping and bake according to the box directions.

Close up of sliced fluffernutter brownies.

More Brownie Recipes to Try

Close up of texture of brownie.
Close up of fluffernutter brownie.
4.34 from 3 votes

Fluffernutter Brownies

Bring a childhood favorite back in the form of rich, decadent brownies. These Fluffernutter Brownies are swirled with peanut butter and sweet marshmallow fluff to make the ultimate dessert.
Prep Time15 minutes
Active Time30 minutes
Total Time45 minutes
Course: Dessert
Cuisine: American
Keyword: fluffernutter brownies
Yield: 12 servings
Author: Meghan Payne-Hensley


  • 3/4 cup butter
  • 3/4 cup cocoa powder
  • 2 cups granulated sugar
  • 4 large eggs
  • 1 teaspoon vanilla extract
  • 1 1/2 cups all-purpose flour
  • 1 teaspoon kosher salt
  • 7.6 ounce bag unwrapped mini reese's peanut butter cups
  • 1/4 cup peanut butter
  • 1/4 cup marshmallow fluff


  • Preheat oven to 350 degrees F. Grease a 9×9 baking pan. Set aside.
  • Heat a large dutch oven or pot over medium heat. Add butter and allow to melt. Whisk in cocoa powder then remove from heat. Stir in sugar. Add eggs and vanilla extract. Whisk until smooth. Stir in flour and salt until you no longer see any flour. Gently fold in peanut butter cups. Spread batter into prepared pan.
  • Place peanut butter in a microwave safe dish. Place marshmallow fluff in another microwave safe bowl. Place in microwave and cook for 20 seconds. Drop dollops of each all over the brownie batter. Swirl with a knife or toothpick. Bake for 25 to 30 minutes, until no longer gooey in the center.

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  1. 5 stars
    Made these with Jared today, great fun and new skill (swirling with a tooth pick) for him.

    1. Yay! I love that Kathe! Hope you enjoyed them!

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