Killer Crunch Brownies

What’s killer (in a totally different way) is that it took me nearly two years to make these killer crunch brownies after a coworker of my husband’s sent me the recipe long, long ago (thanks, Katie!). I was looking through my saved recipes and these caught my eye. And I can attest: they are killer.

Let’s break it down, shall we? A decadent layer of brownies. Check. Topped with luscious marshmallow creme. Got it. Further added upon by a crunchy peanut butter chocolate mixture (think 100-Grand candy bar or something like unto it). Double check. Chilled. Sliced. Devoured.

These are absolutely 100% amazing. Not only are they sinful and rich and totally dreamy, they will wow your friends and family and make you a veritable rock star. These bars are unique, irresistible and anything with the words ‘killer’ and ‘crunch’ in them deserve to be made immediately, in my humble opinion.

Killer Crunch Brownies

Killer Crunch Brownies

Yield: Makes 9X13-inch pan of brownies

Killer Crunch Brownies


  • 1 12-ounce bag chocolate chips
  • 1 cup butter (2 sticks)
  • 1 1/2 cups granulated sugar
  • 1 teaspoon vanilla
  • 4 large eggs
  • 1 1/2 cups all-purpose flour
  • 1/2 teaspoon salt
  • Topping:
  • 7-ounce jar marshmallow crème
  • 1 cup peanut butter
  • 1 cup semi-sweet chocolate chips
  • 3 cups rice krispie cereal


  1. Preheat the oven to 350 degrees. Line a 9X13-inch baking pan with aluminum foil and lightly spray with cooking spray. For the brownies, in a medium saucepan over low heat, 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.
  2. 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, melt the peanut butter and chocolate chips together over low heat, stirring constantly. When fully melted and smooth, remove from the heat and stir in the rice krispies. Scoop spoonfuls 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.

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

46 Responses to Killer Crunch Brownies

  1. Katie says:

    Made these and they are delicious! Do you think the leftovers need to stay refrigerated?

  2. Julie says:

    My grandma made a brownie similar to these, and I have not been able to replicate the crispy peanut butter frosting! I CAN’T wait make these! I’m so excited. Thanks so much!!

  3. Noreen says:

    Unreal. My sister tasted them and I cannot repeat what she said!! So happy I made these. Have already shared with fam and friends. Simply unbelievable.

  4. Eva says:

    Hey Mel- I grew up with these bars. We called them Rocky Road brownies. Delish!


  5. Jamie H. says:

    Mel, I cannot wait to make these. Thank you for sharing them again on the newsletter!

  6. Jenny says:

    I made these last week for a progressive dinner that I hosted and we all LOVED them!!! The texture of them is amazing! Amazingly they didn’t all get eaten so I popped them in the freezer to keep! Let me tell you, still delicious!! Thanks again for another fantastic recipe!

  7. Abbey says:

    Could this be doubled for a jelly roll size pan?

    • Mel says:

      Are you talking about a large, rimmed baking sheet (like 11X17-inches or similar sized)? I think it should work but I haven’t tried it that way before.

  8. angie mitolo says:

    You need a super hero name:)
    I needed a dessert for my daughter’s team party, this one fit the bill. So, easy to make and assemble, since I only had an hour. She came home with an empty dish and raves.
    You Rock!
    Thanks for coming to my rescue.

  9. Marianne Brinker says:

    Hi Mel! So I wanted to let you know that my friends and I follow you, almost exclusively, for recipe ideas. I have tried almost every one and they’re always a hit with my family and friends. You have a huge following in Baraboo, WI! In high school my cross country coach’s Killer Crunch Bars were legendary. The food champions were made of! In a recent try to find them I hadn’t seen anything close but when I found them on your site I was shocked! Even more when I realized you’re from the Green Bay area and so was she and her whole family! Perhaps word has gotten around about their amazingness and your hubby’s co-worker recieved the recipe too. Thanks again!

  10. Maris says:

    Thanks Mel for your quick reply.
    I am baking this for a friend who will be celebrating her wedding anniversary tomorrow.
    Btw, I come from Cebu City, Philippines.

  11. Maris says:

    Hello Mel. I came across your blog searching for extraordinary recipes. Thank you for sharing.
    The 1 pack chocolate chips is equivalent to how many cups?
    I get my chips in kilo bags and would like to be precise in my measurements when i bake this Killer Brownies.
    More power!

  12. Salem says:

    Anyone ever try crunchy peanut butter instead of regular?

  13. Kari says:

    I made these over the weekend and HOLY MAN!! I love them, my kids love them. I had to box up half of the pan and give it away because I knew we would EAT THEM ALL!!! Rich, decadent, easy recipe. No crazy ingredients. I know I will have to make them again, but who can I “force” some of these on next just to not have them in the house??

  14. Lisa says:

    Wow! The way the textures (crunchy, soft, smooth, creamy) and flavors all come together is nothing short of amazing! They really lived up to their name! I had no marshmallow fluff, so I found a recipe here: I found that 1/3 of the recipe made 8 ounces of fluff (in a mixing bowl beat 1 egg white, 2/3 cup corn syrup, and a pinch of salt for 5 minutes or until doubled in size; then add 2/3 cup powdered sugar and 1 tsp. vanilla until well blended). It worked like a charm and I couldn’t believe how easy it was. I don’t think I’ll ever buy marshmallow fluff again. Anyway, I just thought I’d pass that on. Oh, and thanks Mel for such a great blog! I especially appreciate how kind you are to all who comment. Not all food bloggers are.

  15. Olivia says:

    These are good. So. So. So. Soo so sosoosososoosos good. Actually, they are amazing. AH! I love you, Mel! They were good immediately out of the oven and chilled over night in the fridge. Thanks for the awesome recipes!

  16. […] the annual Lund Family Christmas Eve Party. It is huge! We cooked up two hams and I tried a new brownie recipe (Yummy! It was so rich though that I might have to wait until next Christmas Eve to make it […]

  17. Jennifer G. says:

    I made dinner for a family from church and brought a plate of these. I thought they were good but almost too rich and peanuty. I could only eat one and had to cut into tiny squares. I wasn’t sure if I would make again. Then, I brought some into work the next day and I think the flavors had melded into some kind of fabulousness because I liked them much, much better and couldn’t stop trying “just one more bite.” In the future, I will make them a day ahead.That is actually helpful if you need to bring treats somewhere and want to make ahead. They were still just as moist and soft.

  18. Mel says:

    Denise – no, I used regular rice krispies.

  19. Denise says:

    Did you use Cocoa Krispies?

  20. Cathy says:

    Ok, i made these last night and took the brownies out before they were set, and when i put the marshmallow on top i could tell i had to put them back in to cook a few min. more with the marshmallow allready on top and they still turned out great!! LOVE these : ) i also used dark chocolate morsels for the top part!

  21. Melanie says:

    I made these for my husband’s work party and they were a hit! Now to get more marshmallow creme so I can make more for my kids. Maybe this time they will get more than the crumbs.

  22. Christin says:

    These are phenomenal. The crunchy cereal with the gooey brownie is amazing and the flavour combination is perfect.

  23. Katie S. says:

    YEY! So glad you stumbled across the recipe I sent you from 2 yrs ago 😉
    Happy to hear they were a hit. They are pretty darn fantastic!

  24. grace says:

    i love crunch bars and i love brownies. using rice krispies in a crunchy layer is really quite brilliant and i’m glad someone thought of it!

  25. Teresa says:

    Hi Erin
    I have made these with biscoff in place of the peanut butter (my son has a peanut allergy) and they were wonderful!

  26. Diane says:

    We love these and have for many years the cereal freeze’s well!

  27. Laurie says:

    Made them with Michelle and grandkids today. We loved them. We did substitute semi for milk chocolate though. I don’t do dark chocolate in any way shape or form. Will definitely be making these again.

  28. Teresa R. says:

    I had to comment because I just made these for my daughter’s Bible study group tonight. I had all the ingredients and I couldn’t resist. I only kept one small piece for myself…too tempting….and I have to say they are really good – delicious and rich.

  29. Carmen says:

    I’ve been making a version of these for 20+ years! They are great, and great to take. They always get rave reviews.

  30. k says:

    I have almost the same recipe from Betty Crocker…only you use frosting instead of marshmallows and you add peanuts. SO good! I’m gonna have to try it with marshmallow creme and sans peanuts since I somehow have that and not frosting. 😉

  31. Cammee says:

    These will definitely be a hit in my house!

  32. Kelly says:

    I have made these delicious brownies for years and they are loved by all!! If you don’t have marshmallow creme, you can sprinkle mini marshmallows over the top in the last couple minutes of brownie cooking time until they get soft and puffy. Then proceed. JUst a tip to use in a pinch.

  33. Mel says:

    Keri – yes, I use semisweet or bittersweet.

  34. Mel says:

    Kim- as you know, many baked treats freeze perfectly; although I haven’t tried freezing these, I am skeptical on how they would fare thanks to the cereal mixture on top.

    Erin – I know many who are allergic to peanut butter sub soy butter or sunbutter (from sunflower seeds).

  35. Keri says:

    For the brownies, do you use semi-sweet chocolate chips?

  36. Michelle says:

    I have been making these for years, they are the best brownies ever!

  37. Erin says:

    These indeed do look killer, as I’m allergic to peanut butter (and other nuts)! Any ideas for an alternative? Would caramel be too sweet? What about making chocolate rice crispy treats for the top?

  38. EMichelle says:

    My daughter has a Christmas event coming up and I’m thinkin’ these are going to be PERFECT!!!! Thanks for posting this! Merry Christmas! EMichelle

  39. Rae says:

    Yes, these look absolutely killer… killer to the size of my butt!

    I am hypnotizing myself as I type this to forget about this recipe before I make and inhale the entire pan by myself.

  40. JackieToo says:


  41. So I love the combination of peanut butter and marshmallow fluff. Any recipe with those two ingredients is a winner in my book! These look absolutely amazing. And I love how you add rice krispie cereal to give it some texture and crunch. Pinning this to my “need to make asap” board 🙂

  42. Kim in MD says:

    You are “killing” me with all of these awesome desserts, Mel! Everytime I decide which one I am going to make to give away as gifts, you post another amazing recipe that I want to make! These brownies sound incredible. I think I’m going to wait until Sugar Rush 2012 is over before I make my final decision on which treat to make! Another thought I have is to make them all and freeze them, but I’m not sure how some of them (like these brownies) would freeze. Any thoughts? Thanks!

  43. These do sound “killer!”

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