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A stack of Monster Brookie Bars on a cutting board.

Monster Brookies

5 from 34 votes
Gooey brownies with peanut butter, a chocolate chip cookie layer, mini M&Ms and flakey salt.
Servings 24 bars

Ingredients

For the Brownie Layer

  • 1 1/2 cups (180 g) all-purpose flour
  • 3/4 cup (88.5 g) good quality dark chocolate cocoa powder
  • 1 teaspoon (6 g) salt
  • 1 cup (226 g) unsalted butter
  • 1 cup (180 g) bittersweet chocolate chips
  • 2 cups (440 g) light brown sugar, packed
  • 4 eggs
  • 2 teaspoons (8.4 g) vanilla extract
  • 1 cup (180 g) semi-sweet chocolate chips

For the Cookie Layer

  • 3/4 cup (169.5 g) unsalted butter, at room temperature
  • 1/2 cup (100 g) granulated sugar
  • 1/2 cup (110 g) brown sugar, packed
  • 1 egg, at room temperature
  • 1/2 teaspoon (2.1 g) vanilla extract
  • 1 3/4 cups (210 g) all-purpose flour
  • 1 teaspoon (4 g) baking soda
  • 1 teaspoon (6 g) salt
  • 1 cup (180 g) semi-sweet or dark chocolate chips

Fillings and Garnish

  • 1 cup (250 g) peanut butter, melted
  • 1/2 cup (112 g) mini M&Ms
  • Flakey salt

Instructions

For the Brownie Layer

  • Preheat your oven to 350 degrees F. Spray a 9" x 13" baking dish with nonstick spray. Line the bottom and sides with parchment paper. Spray again. Set aside.
  • In a medium size mixing bowl, whisk together the flour, cocoa powder, and salt. Set aside.
  • In a medium size saucepan, melt the butter and the bittersweet chocolate chips until smooth. Remove from the heat and allow to cool for about 5 minutes.
  • Add the brown sugar to the butter and chocolate mixture and stir until smooth.
  • Add the eggs, one at a time, stirring well between each addition.
  • Stir in the vanilla.
  • Add the flour mixture and stir until no streaks of flour remain.
  • Fold in the 1 cup of the semi-sweet chocolate chips.
  • Pour the batter into the prepared pan.
  • Bake the brownies for 15 minutes.
  • While the brownies bake, make the cookie dough. (Instructions below)
  • When the 15 minute timer is up, remove the pan from the oven. Pour the melted peanut butter on top and gently spread into an even layer.
  • Using your hands, break apart the cookie dough (instructions below) and drop on top of the peanut butter and brownie. This does not need to be spread out. It will spread as it cooks.
  • Evenly sprinkle the mini M&Ms on top.
  • Bake for 30 minutes more minutes.
  • The top of the cookie layer will be golden brown. Don’t let that scare you that it’s over cooked. The centers will still be gooey and you’ll get a delicious crunch with each bite, as well.
  • Remove the pan from the oven and sprinkle on the salt.
  • Allow the bars to cool in the pans for at least an hour.
  • The centers will still be gooey after they cool for an hour. If you want the centers more set, allow the bars to sit for an additional hour or two.

For the Cookie Layer

  • In the bowl of an electric mixer fitted with the paddle attachment beat the butter until smooth.
  • Add the sugars and beat until light and fluffy, about 2 minutes. Scrape down the sides of the bowl.
  • Add the egg and mix until well incorporated. Scrape down the sides of the bowl. Add the vanilla and mix for about 30 seconds.
  • With the mixer on low speed, add the flour, baking soda, and salt. Mix until combined. 
  • Stir in the chocolate chips.
Course: Dessert
Cuisine: Bars
Keyword: Brookies, Brownies, cookies, Monster Brookies