This post may contain affiliate links.
Marshmallow Crunch Brownies are the ultimate three-layer brownie!! They start with a box of fudgy brownies followed by a chewy marshmallow layer and are topped with a chocolate peanut butter Rice Krispie topping. Three layers of flavor, texture, and brownie perfection!!
Why You’ll Love This Recipe
These brownies are so easy to make and has simple ingredients (just 5 of them plus the oil/eggs for the brownies) you likely already have on hand!!
They’re perfect for lots of occasions. Potlucks, bake sales, tailgates, birthday parties, and any time you need to feed a crowd….just be prepared for recipe requests, and lots of ’em!
You’ll also love that it all starts with a boxed brownie mix, which saves time and gets these brownies in the oven ASAP! And that crunchy topping is everything (and why some people call these Killer Crunch Brownies)…give it a try and you’ll be hooked! 😉
Ingredients Needed (Full list with amounts in recipe card below)
- Brownie Mix – You can use your favorite box mix (just be sure it’ll work in a 9×13 inch pan) or make your own homemade brownies!
- Mini Marshmallows – Make sure they’re fresh; nobody wants dried-out marshmallows in their brownies!
- Chocolate Chips – Semi-sweet is my preference (as it balances out the sweetness of the marshmallows) but milk chocolate is good too (reminds me of a Star Crunch treat!).
- Peanut Butter – Use regular creamy peanut butter (don’t use natural peanut butter as it won’t have the same texture.
- Rice Krispies Cereal – Or whatever brand of “crispy rice cereal” you have available;)
How to Make Marshmallow Crunch Brownies
Mix Up and Bake the Brownies
You’ll follow the instructions on your boxed brownie mix to make these in a 9×13-inch pan.
Add the Marshmallows
Then you’ll add the marshmallows and return the pan to the oven for just a couple minutes. The marshmallows will soften and puff up a bit to make a nice even layer. Give the brownies some time to cool while you make the topping.
Add the Peanut Butter Chocolate Rice Krispie Topping
In a microwave-safe bowl, you’ll melt the chocolate and peanut butter together. Be sure to stir frequently so the chocolate doesn’t burn and become gritty.
When the chocolate is totally melted, stir in the cereal. Once coated, spoon the mixture over the marshmallows and spread to an even layer.
Let the brownies cool completely before cutting into squares so you have nice clean cuts and optimal texture. You can let them cool at room temperature or chill in the fridge to speed it up! (I know, I’m impatient, too!)
Frequently Asked Questions
You can make these with almond butter or sunbutter in place of the peanut butter! If you’re wanting to steer clear of any peanut allergy situation, double-check the brownie mix to ensure it’s made in a peanut-free facility.
Yes, but it will change the texture. They’ll be more gooey and more challenging to cut into nice squares due to the softness of the fluff.
Yes, but if you do, I’d reduce the cereal to 2 1/2 cups to ensure you have enough chocolate to mix-in ratio! If you’re looking for something similar with more peanut crunch, I highly recommend my Rocky Road Brownies!!
Storage Instructions
Store at room temperature or in the fridge for up to 5 days in an airtight container. I personally prefer these refrigerated so the marshmallows are extra chewy!
You can also store them in the freezer! Just place the brownies in freezer baggies for up to 2 months!
Other Brownie Recipes To Try!
- Rocky Road Brownies
- Toffee Brownies
- Cheesecake Brownies
- Snickers Brownies
- Turtle Brownies
- Oreo Brownies
- Brownie Bites
Marshmallow Crunch Brownies
Equipment
- 1 9×13-inch pan
Ingredients
- 1 box brownie mix plus ingredients called for on the box mix
- 3 cups mini marshmallows
- 12 ounces semi-sweet chocolate chips (2 cups)
- 1 cup creamy peanut butter
- 3 cups Rice Krispies cereal
Instructions
- Prepare the brownie mix according to the box instructions. (Be sure that you’re preparing it in a 9×13 pan – some brownie mixes these days only fit an 8×8 square pan.)1 box brownie mix
- Remove the brownies from the oven and immediately put sprinkle the marshmallows over-top; return to the oven for 3 minutes.3 cups mini marshmallows
- While the brownies cool a bit, make the topping.
- In a microwave-safe bowl, stir together the chocolate chips and peanut butter; microwave in 30 second intervals, stirring after each one, until smooth.12 ounces semi-sweet chocolate chips, 1 cup creamy peanut butter
- Add the Rice Krispies stir until evenly coated.3 cups Rice Krispies cereal
- Carefully spoon the mixture over the marshmallow-covered brownies and use a rubber spatula or knife to spread it out evenly.
- Cool the bars completely before cutting and enjoy! (You can put them in the fridge to help set the bars more quickly!)
Notes
- Peanut Butter – Use almond butter or sunbutter in place for a good peanut-free option.
- Mini Marshmallows – You can cut regular-sized marshmallows in half to cover the brownies or use marshmallow creme (though it’ll much a much softer texture and less chewy).
