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A single fudgy marshmallow peanut butter brownie on a white surface, showcasing the chewy texture and distinct layers.

Marshmallow Peanut Butter Brownies: The Ultimate Fudgy & Gooey Guide

The ultimate recipe for Marshmallow Peanut Butter Brownies! This guide delivers perfectly fudgy, chewy brownies with a rich peanut butter swirl and a gooey, toasted marshmallow topping. An easy-to-follow, decadent dessert for any occasion.
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Prep Time 15 minutes
Cook Time 33 minutes
Total Time 48 minutes
Servings: 16 brownies
Course: Dessert
Cuisine: American
Calories: 250
Ingredients Equipment Method Notes

Ingredients
  

For the Brownie Base
  • 1/2 cup unsalted butter melted
  • 1 cup granulated sugar
  • 1/4 cup packed brown sugar
  • 2 large eggs room temperature
  • 1 teaspoon vanilla extract
  • 3/4 cup all-purpose flour
  • 1/2 cup unsweetened cocoa powder
  • 1/4 teaspoon salt
  • 1/2 cup semi-sweet chocolate chips
For the Peanut Butter Swirl
  • 1/2 cup creamy peanut butter
  • 2 tablespoons powdered sugar
For the Marshmallow Topping
  • 2 cups mini marshmallows

Equipment

  • 1 8x8 inch baking pan
  • 2 Mixing bowls
  • Parchment Paper

Method
 

  1. Preheat oven to 350°F (175°C). Grease and line an 8x8 inch baking pan with parchment paper. In a small bowl, mix the creamy peanut butter and powdered sugar until combined. Set aside.
  2. In a large bowl, whisk together melted butter, granulated sugar, and brown sugar. Add eggs and vanilla extract, mixing until fully incorporated.
  3. In a separate bowl, sift together flour, cocoa powder, and salt. Add the dry ingredients to the wet ingredients and mix until just combined. Do not overmix.
  4. Fold in the semi-sweet chocolate chips. Pour batter into the prepared pan. Dollop the peanut butter mixture over the top and use a knife to gently swirl it into the batter.
  5. Bake for 25-30 minutes, or until a toothpick inserted into the center comes out with moist crumbs.
  6. Remove from oven and sprinkle mini marshmallows evenly over the top. Return to the oven for 2-3 minutes until marshmallows are puffy. Optional: Broil for 30-60 seconds for a toasted top, watching carefully.
  7. Let the brownies cool completely in the pan before lifting out with the parchment paper and cutting into 16 squares.

Notes

Do not overmix: For the fudgiest texture, mix the batter until just combined.
Cool completely: This is crucial for clean cuts and allowing the brownies to set properly.
Storage: Store in an airtight container at room temperature for up to 3 days.