Go Back
Close-up shot of a thick, fudgy chocolate brownie bar square, generously topped with a layer of gooey, lightly toasted golden-brown mini marshmallows and thick, glossy swirls of creamy peanut butter. (Marshmallow peanut butter brownies)

The Ultimate Marshmallow Peanut Butter Brownies

Decadent Marshmallow peanut butter brownies featuring a dense, fudgy dark chocolate base, shiny cracked edges, toasted golden-brown mini marshmallows, and thick, glossy peanut butter swirls. An incredibly rich, texturally perfect dessert.
Print Recipe Pin Recipe
Prep Time 15 minutes
Cook Time 30 minutes
Total Time 45 minutes
Servings: 16 slices
Course: Dessert, Snack
Cuisine: American
Calories: 320
Ingredients Equipment Method Notes

Ingredients
  

Marshmallow Peanut Butter Brownies Ingredients
  • 8 oz high-quality dark chocolate (226g) 60-70% cacao, roughly chopped
  • 1/2 cup unsalted butter (115g)
  • 1 cup granulated sugar (200g)
  • 1/2 cup light brown sugar (100g) packed
  • 3 large eggs room temperature
  • 1 tsp pure vanilla extract (5ml)
  • 1/2 cup unsweetened cocoa powder (60g) Dutch-processed preferred
  • 3/4 cup all-purpose flour (95g)
  • 1/2 tsp fine sea salt (3g)
  • 2 cups mini marshmallows (100g) fresh
  • 1/2 cup creamy peanut butter (125g) commercial brand, not natural

Equipment

  • 1 8x8-inch light-colored metal baking pan Ensures even baking without burning the edges.
  • 1 Electric Hand Mixer or Stand Mixer Essential for whipping the eggs and sugar to create the shiny top.

Instructions
 

Baking the Brownies
  1. Preheat your oven to 350°F (175°C). Line an 8x8-inch baking pan with crinkled parchment paper, leaving a slight overhang.
  2. In a microwave-safe bowl, combine the chopped dark chocolate and unsalted butter. Microwave in 30-second bursts, stirring until smooth. Set aside to cool slightly.
  3. In a large mixing bowl, beat the eggs, granulated sugar, and brown sugar with a mixer on medium-high for 3 to 4 minutes until pale and thick.
  4. Gently fold the cooled melted chocolate mixture and vanilla extract into the whipped eggs using a rubber spatula.
  5. Sift the flour, cocoa powder, and sea salt over the wet ingredients. Fold gently until no streaks of flour remain.
  6. Pour the batter into the prepared pan and bake for 25 to 28 minutes, until a toothpick inserted into the center comes out with moist crumbs.
  7. Remove the pan from the oven and sprinkle mini marshmallows evenly over the top. Switch the oven to broil (high) and broil for 1 to 2 minutes until marshmallows are golden-brown. Watch carefully!
  8. Microwave the peanut butter for 20-30 seconds until warm and pourable. Drizzle it over the hot, toasted marshmallows and gently swirl with a knife or toothpick. Let cool completely before slicing.

Notes

Tip 1: Do not use natural peanut butter; it will separate and ruin the glossy finish.
Tip 2: To slice cleanly through gooey marshmallows, run a sharp knife under hot water, dry it, and coat lightly with cooking spray between cuts.
QR Code linking back to recipe