Fluffernutter Brownies (brownies with marshmallow fluff and peanut butter)

I’ve been wanting to share this recipe for a while, but since today is #NationalPeanutButterLoversDay, I thought it was the perfect time. Introducing a DELICIOUS new peanut butter marshmallow brownies recipe: Fluffernutter Brownies! For those that don’t know, a “fluffernutter” is a sandwich made with peanut butter and marshmallow fluff (think of a PB&J, but with marshmallow crème subbed for the jelly). These are brownies with marshmallow fluff and a creamy peanut butter topping swirled on top, hence the name “Fluffernutter Brownies.” This is a variation on my classic foolproof brownies recipe, but with a lovely peanut butter marbled brownies topping. Whether for National Peanut Butter Lovers Day, a party, or anytime you want to treat yo’self, you’ll definitely want to save this decadent peanut butter and marshmallow fluff brownies recipe. I’ve got some of my cooking tips for making it below, or feel free to scroll to the end of the post for the full recipe.

Want more recipes like these fluffernutter bars? More brownies variations:

How to make Fluffernutter Brownies (brownies with marshmallow fluff and peanut butter)

Start this peanut butter and marshmallow fluff brownies recipe by preheating the oven to 350 degrees F, lining a 9″x13″ baking pan with parchment paper, and spraying the parchment paper with non-stick cooking spray. Note: If you don’t have parchment paper, this recipe will still work without it. I just prefer parchment paper for making the brownies easier to remove and slice. If you don’t have parchment paper, just spray the baking pan with non-stick spray and cook directly in the pan.

Mix the sugar, flour, cocoa powder, salt, and baking powder together in a mixing bowl. Then, mix 3/4 cup of the melted butter,* eggs, and vanilla extract together in a separate bowl.

*Important tip: In order to make these brownies foolproof, it’s important to use real butter, not margarine, for this recipe. I’ve tried it with margarine and it never turns out the right consistency.

Add the butter mixture to the bowl with the flour mixture and stir the fluffernutter brownies batter until well mixed.

Spread the batter into the prepared baking pan and set it aside.

Warm the peanut butter in the microwave for 30 seconds to soften. Using a stand or hand mixer, beat the remaining 3 tablespoons of melted butter, the softened peanut butter, and confectioners sugar together at medium speed until everything is well mixed.

Place dollops of the peanut butter topping on top of the brownie batter in the pan.

Now, warm the marshmallow creme (or marshmallow fluff) in the microwave for 30 seconds to soften. Add dollops of the marshmallow creme on top of the brownie batter in alternating spots from the peanut butter. Don’t worry if the dollops aren’t perfect… you’re about to swirl it all up anyway!

Using a butter knife held upright, dip through the dollops and into the batter, then drag the knife to one side of the baking pan to create a swirled marbling effect with the toppings and batter.

Repeat in rows, then do the same going up and down…

…then diagonally until you’ve got a nice swirl pattern.

Bake in the preheated oven until the edges are brown and the center is set, about 30-35 minutes. Remove the pan from the oven and let the fluffernutter brownies cool completely (about 30 minutes).

Remove the brownies with marshmallow fluff and peanut butter from the pan by lifting the parchment paper (with the brownies) out of the pan. Slice and serve!

These peanut butter marshmallow brownies are gooey in the center… just how brownies should be!

Aren’t these peanut butter marbled brownies pretty?

Here’s the Fluffernutter Brownies recipe, just in time for #NationalPeanutButterLoversDay. Enjoy, and don’t forget to leave a rating after you make it!