When You Cross a Monster Cookie with a Fudgy Brownie…

Monster Brownie n

A decadent, sweet confection stuffed with peanut butter and chocolate and decorated with the fun colors of M&Ms. This Monster Brownie is a rich, colorful dessert delicious for any age.

Once a month or so, I bake for my students. They earn tickets in the classroom and can spend the tickets on “bake sale” day. It’s a tasty incentive that allows me to bake, which I enjoy, and allows them to have a tasty reward for their hard work and good behavior. My bake sales have created monsters… cookie monsters! After the first couple of baking events, my students started to come up with ideas and challenges for me to bake. One of the first rewards was a fudgy brownie with a chocolate ganache frosting. Of course, this went over quite well. Several bake sales later, I brought in mini monster cookies… which were an instant hit. One day, my cookie monsters were arguing over the best baked treat I had brought them. It was fudgy brownies versus monster cookies. There was only one way to settle this argument… a confection made up of all the flavors of both of these confections. So, monster brownies were born.

As you might guess, the monster brownies came out fantastically. The fudginess of the original brownie recipe was retained. Swirling in a peanut butter mixture, instead of mixing in peanut butter, kept the peanut butter flavor as an upfront flavor. After mixing in the M&Ms, I reserved a few extra M&Ms to speckle the top to make sure there was no mistake that this was a monster brownie! My bake sale “customers” were extremely happy.

Monster Brownies


Brownie Batter

  • 10 tbsp unsalted butter, melted
  • 1 1/4 cups granulated sugar
  • 3/4 cup unsweetened Dutch-processed cocoa powder
  • 1/2 cup all-purpose flour
  • pinch salt
  • 1/2 tsp vanilla extract
  • 2 large eggs
  • 2/3 cup M&Ms

Peanut butter filling

  • 4 tbsp unsalted butter, melted (Use a quality brand made only of roasted peanuts or roasted peanuts and a dash of salt, such as Laura Scudder’s or Adams.)
  • 1/2 cup confectioner’s sugar
  • 3/4 cup natural peanut butter
  • pinch salt
  • 1/2 tsp vanilla extract


  1. Preheat oven to 325 degrees F (160 degrees C).
  2. Line an 8 x 8 inch glass baking dish with foil. Grease foil. Set aside.
  3. In a medium bowl, mix together melted butter and sugar.
  4. Sift in cocoa powder and flour to eliminate lumps.
  5. Mix well.
  6. Mix in vanilla and eggs.
  7. Fold in M&M pieces.
  8. Set aside and make peanut butter filling.
  9. In another medium bowl, mix filling ingredients together until mixture is smooth.
  10. Pour about 1/2 of the brownie batter evenly into prepared baking dish.
  11. Scoop tablespoons of peanut butter filling and drop onto brownie batter.
  12. Pour remaining batter on top of peanut butter filling.
  13. Gently drag a butter knife through all layers going from left to right and from top to bottom in order to slightly mix batter.
  14. Bake for about 50 minutes. A wooden stick inserted into brownies will have a few crumbs and not be wet. Check the brownies away from the edge and away for the middle for best results.
  15. Let cool slightly in pan. Finish cooling on wire rack.
  16. Cut when completely cooled.

6 thoughts on “When You Cross a Monster Cookie with a Fudgy Brownie…

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