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Marshmallow Crunch Brownie Bars - A stack of brownies with a layer of marshmallows and crisp chocolate and peanut butter topping.

Marshmallow Crunch Brownie Bars

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Super fudgy brownies topped with a layer of marshmallows and a chocolate, peanut butter and Rice Krispies mixture.
Course Snack
Cuisine American
Prep Time 30 mins
Cook Time 30 mins
Total Time 1 hr
Servings 24 bars
Calories 340
Author Michelle


For the Brownie Base

  • 4 ounces unsweetened chocolate
  • cup unsalted butter
  • cups semisweet chocolate chips, divided
  • 1⅓ cups all-purpose flour
  • 1 teaspoon baking powder
  • ½ teaspoon salt
  • 4 eggs at room temperature
  • 2 cups granulated sugar
  • 2 teaspoons vanilla extract

For the Marshmallow Layer

  • 10.5 ounce bag miniature marshmallows

For the Crispy Chocolate Peanut Butter Layer

  • cups milk chocolate chips
  • 1 cup smooth peanut butter
  • 1 tablespoon unsalted butter
  • cups Rice Krispies cereal


  • Make the Brownies: Preheat the oven to 350 degrees F. Grease a 9x13-inch pan.
  • In a medium saucepan, melt the unsweetened chocolate, butter and ¾ cup of the semisweet chocolate chips over medium heat. Stir occasionally while melting. Set aside and cool for 5 minutes.
  • In a large bowl, whisk the eggs thoroughly. Add the sugar and vanilla, and whisk until well blended. Stir the melted ingredients into the egg mixture, mixing well. Sift the flour, baking powder and salt into the mixture and stir well. Fold in the remaining ½ cup semisweet chocolate chips.
  • Pour the batter into the prepared pan, smoothing it into an even layer. Bake for 25 to 30 minutes, or until a toothpick inserted into the corner of of the pan comes out with moist crumbs.
  • Remove the brownies from the oven and immediately sprinkle the marshmallows over them. Return the pan to the oven for 3 more minutes.
  • Make the Crispy Chocolate Peanut Butter Layer: Meanwhile, place the milk chocolate chips, peanut butter, and tablespoon of butter in a medium saucepan. Melt over low heat, stirring constantly, until completely melted. Remove from heat, add the Rice Krispies and mix well. Allow to cool for 3 minutes.
  • Spread the mixture evenly over the marshmallow layer. Allow to cool to room temperature, then refrigerate for 30 minutes to make it easier to slice. The brownies can be stored at room temperature or in the refrigerator for up to 1 week.


  • Do not use natural peanut butter, as it is too oily.
  • I have made this successfully with Sunbutter (the natural version, with yellow lid) in place of the peanut butter with no issues.
  • Since originally making this recipe, my better-than-box-mix brownies have become my go-to recipe for brownie creations, so I recommend using that one as the base!
Nutritional values are based on one serving


Calories: 340kcal | Carbohydrates: 44g | Protein: 6g | Fat: 16g | Saturated Fat: 8g | Cholesterol: 44mg | Sodium: 145mg | Potassium: 222mg | Fiber: 2g | Sugar: 29g | Vitamin A: 360IU | Vitamin C: 1.1mg | Calcium: 45mg | Iron: 2.6mg