Marshmallow Peanut Butter Crunch Brownies

Fudgy, dark chocolate brownies topped with marshmallow fluff and then a peanut butter chocolate crunch top for the most delicious layered brownie dessert!

These Marshmallow Peanut Butter Crunch Brownies have been a favorite recipe in our family for years. I can’t believe it’s taken me this long to put this post up!! I did have this on my old blog (there’s a blast from the past! 😆); so we haven’t been without being able to look up the recipe, but I have had family members asking for it to be up here! Finally, about 8 years later, I’m getting to it! 😁

While I was editing these photos, I realized I had just posted a brownie recipe…I must have some serious brownie cravings happening since that’s all I seem to want to post about! 😂 This recipe checks the boxes for being a perfect dessert in my book – so good and super easy to make! This is one of Caitlin’s favorite desserts and something she even requests for her birthday sometimes since she’s not a huge fan of cakes. I’m more than happy to make this anytime!

close up of Marshmallow Peanut Butter Crunch Brownie bar

This dessert starts with a brownie layer base. I use Betty Crocker’s Dark Chocolate brownie mix for this recipe; my boys love these, and they are not fans of dark chocolate, so don’t be scared away if you’re not into dark chocolate. The brownies are topped with marshmallow fluff and then a chocolate peanut butter rice krispies topping! Combine those and you’re left with delicious brownie layer bars that you’re not going to want to stop eating!

brownie bar dessert cut into triangles on parchment paper with jar of milk
dessert brownie bar close up sitting on enamel pie plate
loaf pan filled with Marshmallow Peanut Butter Crunch Brownies
Marshmallow Peanut Butter Crunch Brownies

Fudgy, dark chocolate brownies topped with marshmallow fluff and then a peanut butter chocolate crunch top!

Course: Dessert, Snack
  • 1 (20-ounce) box of brownies (9×13 pan size), plus ingredients listed on box (I like to use Betty Crocker's Dark Chocolate mix for this)
  • 2 cups marshmallow fluff
  • 2 cups chocolate chips (can be semi-sweet or milk chocolate)
  • 1 cup creamy peanut butter
  • 4 cups rice krispies cereal
  1. Make brownies, following directions on box, using a 9×13 pan. (Make sure you don't over-bake your brownies, I like to take mine out about 3 minutes earlier than the suggested time!). Let cool.

  2. Spread cooled brownies with 2 cups of marshmallow fluff. (For easier spreading, heat fluff briefly in microwave, 20-30 seconds, to soften it).

  3. Add the 2 cups of chocolate chips and 1 cup of peanut butter to a medium, microwave safe bowl. Heat in microwave one minute. Stir. Heat an additional 30 seconds, or until the chocolate chips are just starting to melt. Stir until smooth.

  4. Add the 4 cups of rice krispies and stir to evenly coat the cereal.

  5. Pour the rice krispies mixture on top of the fluff and spread to evenly cover.

  6. Refrigerate until set. Or if you're impatient like me, freeze till set.

  7. Cut into bars & enjoy!

  8. Store in airtight container (refrigerator is best, as the marshmallow can start to ooze and the chocolate will start to melt).

triangle cut dessert brownie bars on wood cutting board
pie plate with triangle cut Marshmallow Peanut Butter Crunch Brownies next to jar of milk

For more brownie recipes, check out our Chocolate Chip Skillet Brookie and these Creme Egg Brownies.


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