If you love the yummy taste of a classic peanut butter and fluff sandwich, you will love these Peanut Butter & Marshmallow Brownies. My classic peanut brownie recipe is made even tastier with swirls of Marshmallow Fluff. These are so good that you will not be able to eat just one!
Peanut butter and fluff sandwiches are my guilty pleasure. I am not even really a sweets kind of person, but at the tender age of 10, I feel in love with this classic combo.
Even now, my son still loves his weekly PB & Fluff sandwich, and I occasionally will indulge in one.
5 years ago, I created my own (from scratch) peanut butter brownie recipe that is so heavenly. With over 50k Pinterest shares, this recipe has become a hit!
Last month, I reinvented my brownie recipe by adding Nutella to them, and most recently marshmallow fluff.
I wasn’t quite sure how the marshmallow would bake up and was hoping that they would turn out nicely. My main concern was if they would be easy to cut.
After taking them out of the oven, they were a success! I allowed them to cool for 1 hour before removing the parchment-lined brownies from my pan.
I used a wet butter knife to slice through them, and they cut perfectly!! I could already tell the slightly stick, crispy, marshmallow topping was baked to a perfection.
Peanut Butter- I used a creamy variety, but have made these with crunchy as well.
Eggs- two large eggs help to bind ingredients, and make these brownies slightly cakey.
Butter- be sure you heat the butter until it is just melted.
Sugars- both granulated and light brown come together to make this recipe a hit!
Flour- All-purpose flour works best in this recipe.
Baking powder- needed to help these rise.
Salt- just a pinch goes a long way to enhance the flavors.
Vanilla extract- Needed to add the perfect hint of vanilla to these brownies.
Marshmallow Fluff- my favorite ever! Be sure to heat it for 15 seconds to make swirling easy!
I love these peanut butter brownies because they are made in one bowl.
Simply whisk the dry ingredients, and fold in the wet ingredients until fully combined.
This batter will be thick and is best spread using a rubber spatula.
Use a wooden skewer to swirl on warmed marshmallow onto the top of the batter.
Bake for 25 minutes on the center oven rack at 350 degrees Fahrenheit.
Line the 11″ x 9″ with parchment paper for easy cleanup and cutting! Use a wet knife to cut through brownies easily once fully cooled.
These brownies freeze very well. Be sure to package in an airtight container and freeze for up to 30 days. Thaw and reheat in the microwave to warm.
More tasty recipes for PB lovers
Peanut Butter and Marshmallow Brownies
- 11" x 9" brownies
- 1 cup all-purpose flour
- 1 tsp. baking powder
- 2/3 cup granulated sugar
- 1/2 cup brown sugar
- 1/8 tsp. kosher salt
- 1 tsp vanilla extract
- 1/2 cup creamy or chunky peanut butter
- 1/3 cup butter melted
- 2 large eggs
- 1/2 cup marshmallow fluff warmed for 15 seconds.
- Preheat oven to 350 degrees Fahrenheit. Line an 11″x 9″ brownie pan with parchment paper so you can easily lift your brownies right out once they are cooled. (This is optional, but makes removing the brownies and cleaning way easier!)
- In a large bowl, whisk the dry ingredients together.
- Add the wet ingredients directly to the dry ingredients, and mix thoroughly with a wooden spoon.
- Spread the batter onto a parchment-lined brownie pan. Spread evenly in the pan with a rubber spatula.
- Add 5-6 small plops of warmed marshmallow to the top of your batter. Use a wooden skewer to swirl the marshmallow on top of their brownies.
- Bake on center rack of your oven for 25 minutes. Brownies will have a golden brown edge and moist (but not raw) inner.
- Allow brownies to cool for at least one hour before cutting. Cooling will also let the brownies naturally harden a bit.
- Remove brownies from pan and use a wet knife to cut them into 12 pieces.