These killer crunch brownies are a brownie explosion! Fudgy brownies, sweet marshmallow cream, and crispy chocolate peanut butter topping.

One of my favorite desserts on the planet, these killer crunch brownies are something special. 

Texturally, they are perfect. Fudgy brownie + creamy marshmallow filling + crunchy topping. Seriously, amazing. 

Killer crunch brownie on white paper with bite taken out.

But the flavors are spot on delicious, too. The hint of peanut butter in the rice krispie topping is heavenly with the marshmallow and brownie layers. 

Brownie square on wood cutting board.

Rice Krispies for Life

The marshmallow layer in these brownies is good and all, but it’s the crispy peanut butter chocolate layer that is absolutely stellar. 

Something about adding that light and airy crunchiness to the top of the rich, soft brownie does something inherently good for my soul. 

Killer crunch brownie broken in half and stacked on white parchment paper.

Easiest Brownies in the World

The brownie base for these killer crunch brownies is from one of my favorite brownie recipes. A bag of chocolate chips, some butter, a bit of sugar and flour is about all you need to make rich, decadent brownies. 

It’s the perfect recipe for layering on marshmallow fluff and then the crispy topping. 

The recipe makes one 9X13-inch pan of brownies, but it can easily be doubled for a half sheet pan or for two pans of brownies (I mean, why not??).

Pouring brownie batter into 9X13-inch pan.

While the brownies are still warm, right out of the oven, dollop the marshmallow fluff (or creme) over the top in large spoonfuls. 

Wait a minute or two and then spread the sticky glorious stuff into an even layer. It’s ok if a tiny bit of the brownie top pulls up into the marshmallow fluff. 

It doesn’t have to be perfect, and I promise, regardless of imperfections, these brownies are going to taste amazing.

Marshmallow cream dolloped across top of warm pan of brownies.

Crispy Topping 

The crispy topping is just three easy ingredients: 

  • peanut butter
  • chocolate chips
  • crisp rice cereal

Melt the peanut butter and chocolate together and stir in the rice krispies. Stir gently so the rice cereal doesn’t disintegrate – but if the PB/chocolate mixture is warm enough, this is a very easy process. 

Stirring rice krispies into peanut butter chocolate mixture.
Peanut butter, chocolate and rice krispy filling in glass bowl.

Pile that glorious concoction on top of the marshmallow fluff and use an offset spatula to spread into an even layer. 

I like to gently press on the top of this chocolatey cereal layer once it’s spread evenly to compress it just every so slightly. 

It should be relatively smooth. As smooth as a rice krispie layer can be. 

Spreading crispy peanut butter chocolate topping on top of marshmallow cream on brownies.
Side by side pans of brownies with marshmallow cream and rice krispie topping.

Killer Crunch Brownies

Once you experience these killer crunch brownies, I’m just warning you that it’s hard to go back to every day brownies again. 

They are unique and just different enough to be super appealing…while not being so *out there* that they make people feel uncomfortable (you know what I mean?). 

Every time I make these for a potluck or gathering, they are one of the first things to go. They are a showstopper and rightly so. They taste even more amazing than they look!

Killer crunch brownie on white piece of parchment paper.

Killer Crunch Brownies

4.59 stars (65 ratings)



  • 1 (12-ounce) bag (340 g) chocolate chips, (2 cups)
  • 1 cup (227 g) butter
  • 1 ½ cups (318 g) granulated sugar
  • 1 teaspoon vanilla
  • 4 large eggs
  • 1 ½ cups (213 g) all-purpose flour
  • ½ teaspoon salt


  • 1 (7-ounce) jar (198 g) marshmallow crème
  • 1 cup (255 g) peanut butter
  • 1 cup (170 g) semi-sweet chocolate chips
  • 3 cups rice krispie cereal


  • Preheat the oven to 350 degrees. Line a 9X13-inch baking pan with aluminum foil or parchment paper and lightly spray with cooking spray (helps with cleanup and lifting out the bars).
  • For the brownies, in a medium saucepan over low heat or in a microwave-safe bowl in the microwave, melt the butter and chocolate chips. Stir constantly and remove from the heat when the chips are fully melted.
  • Whisk in the sugar and vanilla. Add the eggs, blending fully, one at a time. Add the flour and salt and mix until well combined. Pour the batter into the prepared pan. Bake for 25-30 minutes until the brownies are cooked through and set but not overbaked.
  • While the brownies are still warm, dollop the marshmallow crème over the top in large scoops and spread into an even layer.
  • In a medium saucepan or in a microwave-safe bowl in the microwave, melt the peanut butter and chocolate chips together over low heat, stirring constantly, until melted and smooth. Remove from the heat and stir in the rice krispies until evenly coated.
  • Scoop spoonfuls of the crispy topping over the marshmallow layer and gently spread into an even layer. Let the pan of brownies cool to room temperature and then refrigerate until the chocolate krispie topping is set, 1-2 hours. Serve chilled or at room temp.
Serving: 1 Brownie, Calories: 338kcal, Carbohydrates: 39g, Protein: 5g, Fat: 19g, Saturated Fat: 9g, Cholesterol: 54mg, Sodium: 199mg, Fiber: 1g, Sugar: 26g

Recipe Source: adapted from a recipe Katie S. (who works at the company my husband used to work at) sent me a couple of years ago

Recipe originally posted Dec 2012; updated March 2021 with new pictures, recipe notes, etc.

brownie bottom, marshmallow middle, and crunchy topped chocolate bar cut in a small square