These peanut butter marshmallow Krispie topped brownies are the perfect sweet treat. Brownies topped with melted marshmallows and peanut butter chocolate Krispie crunchy treats.

If you’re looking for the PERFECT brownie bar cookie dessert recipe I have you covered! 

These peanut butter marshmallow Krispie topped brownies are sweet, full of chocolate flavor, and are super simple to throw together. 

They are made super easy by using box brownies but you could easily substitute your favorite homemade brownie in place. 

The topping brings a big bite of texture and the addition of peanut butter gives it that classic chocolate peanut butter combo. 

Oh, and then I threw in some marshmallows to bring in a whole s’mores vibe. 

It’s a flavor party in your mouth. 

Plus it’s a great potluck dessert because a little goes a long way this decadent treat!

Can I cut this recipe in half?

Yes!

You can simply bake the boxed brownies in a 9×9 pan instead of a 9×14 pan. The brownies will be thicker but you only need to cover half as much.  

Just make sure to use a boxed brownie that can be baked in a 9×9 or an 8×8 pan. Some brownie mixes are specifically made for baking in a smaller pan. My favorite is the Ghirardelli boxed brownies!

Or, sometimes you can find smaller sized brownie mixes in pouches. They are usually in the same area as the ready to mix cookies. 

If you opt to cook in a 9×9 you will just cut the topping ingredients by half. 

I know it might be a little tricky to cut the 1/3 cup of chocolate chips in half but I typically just eyeball the half. Since you’re using this chocolate to just coat the Krispie cereal you don’t need to worry about being 100% precise. 

How to store these brownies?

These brownies will keep covered on the counter for 2-3 days.

However, if it’s warm in your house the chocolate topping could become soft and melty. 

If your home is warmer I would suggest covering the pan with plastic wrap or foil and keeping it in the fridge. 

The brownies may be a little hard when you first take them out but they will soften up quickly.

Can I leave out the peanut butter?

Yes, but it will change the texture of the chocolate Krispie topping. 

The peanut butter not only brings flavor but it helps bring in a little fat to the chocolate so it sets up firmly without becoming too hard. 

If you cannot have peanut butter I would suggest swapping it out Nutella or any other type of nut butter. 

Can I use another nut butter?

If you read above you’ll know the answer is yes! 

You can easily substitute almond butter, cashew butter, or even hazelnut butter. 

Honestly, any nut butter you can find. I have not tried using sunflower seed butter but I think it would work fine here too. 

Can I use a different cereal?

Yes, but much like leaving out the peanut butter, changing the cereal will change the texture of the brownies. 

If you’re looking to a healthier alternative to Rice Krispies they make several different puffed brown rice kinds of cereal. They are typically found in the natural section of the grocery store. 

Although, I’m not sure healthy and this recipe goes hand in hand. 

Also, using generic rice cereal in this recipe works out perfectly well! 

Other great options would be lightly crushed rice Chex or corn flakes. 

If you want to go extra chocolate try subbing in cocoa Krispies or Cocoa Pebbles!

Love these peanut butter marshmallow Krispie topped brownies?

Try a few of my other delicious desserts!

•  Peanut Butter Nutella Rice Krispie Treats
• Paleo Gingerbread Blondies
• Cake Batter Rice Krispie Treats
• Homemade Girl Scout Cookies Samoas Bars,
• Peanut Butter Toffee Topped Blondies
• Salted Nut Roll Bars