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Easy monster cookie fudgy brownies – double layer brownies with fudgy chocolate base and chewy monster cookie topping
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Monster Cookie Fudgy Brownies

These Easy Monster Cookie Fudgy Brownies are the ultimate dessert mashup! A super rich and fudgy brownie layer is topped with a chewy monster cookie dough loaded with peanut butter, oats, mini M&M's, and chocolate chips. The best brookie you'll ever make – perfect for sharing. For another incredible brownie recipe, try our Espresso Brownies.
Prep Time30 minutes
Cook Time45 minutes
Total Time1 hour 15 minutes
Course: Dessert
Cuisine: American
Keyword: brookies, monster cookie fudgy brownies, peanut butter oatmeal cookie brownies
Servings: 16 brownies
Calories: 325kcal
Author: Angela

Equipment

  • 9x9-inch Baking Pan Essential for this recipe.
  • Electric Mixer with Whisk and Paddle For beating eggs and creaming butter.
  • Rubber Spatula For gentle folding.
  • Parchment Paper For easy removal.

Ingredients

  • 1.33 cup white granulated sugar
  • 2 large eggs
  • 1 egg yolk
  • 5 tbsp unsalted butter
  • 0.33 cup vegetable or canola oil
  • 1 tsp vanilla extract
  • 0.5 cup all-purpose flour
  • 0.75 cup unsweetened cocoa powder (dutch process)
  • 1 tbsp cornstarch
  • 0.25 tsp salt
  • 0.5 cup semi-sweet chocolate chips
  • 0.5 cup milk chocolate chips
  • 0.5 cup all-purpose flour (for cookie dough)
  • 1 tsp cornstarch
  • 0.5 tsp baking soda
  • 0.125 tsp baking powder
  • 0.25 tsp salt
  • 0.25 cup unsalted butter, room temperature
  • 0.33 cup brown sugar, packed
  • 0.125 cup white granulated sugar
  • 0.25 cup creamy peanut butter
  • 1 tsp vanilla extract
  • 1 large egg, room temperature
  • 0.5 cup quick oats
  • 0.5 cup mini chocolate chips
  • 0.5 cup mini M&M's

Instructions

  • In a medium bowl, whisk flour, cornstarch, baking soda, baking powder, and salt for cookie dough. Set aside.
  • In a mixer, beat butter, brown sugar, and sugar until light and fluffy. Add peanut butter and beat another minute. Add vanilla and egg, mix until combined. Slowly mix in dry ingredients, then stir in oats, M&M's, and chocolate chips. Cover and chill for 40 minutes.
  • Preheat oven to 325°F. Spray a 9x9-inch pan and line with parchment paper. Whisk together flour, cocoa, cornstarch, and salt for brownies. Set aside.
  • In a mixer with whisk, beat sugar, eggs, and egg yolk for 5 minutes until light and fluffy. Melt butter and let cool slightly.
  • Add melted butter, oil, and vanilla to the egg mixture; mix on low. Gently fold in dry ingredients with a spatula, then fold in chocolate chips.
  • Pour brownie batter into pan and bake for 15 minutes. Remove from oven, top with flattened discs of chilled cookie dough. Bake for another 20 minutes, then tent with foil and bake 5-10 minutes more until set.
  • Cool completely in pan on a rack. Once cool, lift out, slice into 16 squares with a clean sharp knife, and serve.

Notes

Pro Tips: Beat the eggs and sugar for a full 5 minutes for that perfect fudgy texture. Chill the cookie dough for 40 minutes – it's essential for handling. Don't skip the par-bake of the brownie layer. Cool completely before slicing for the richest flavor and cleanest cuts. For extra color, sprinkle more M&M's on top before the final bake. These brownies are even better the next day!