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5 from 2 votes

Marshmallow Brookies

A layer of chocolate chip cookie, topped with brownie, and smothered in toasted marshmallows
Prep Time20 mins
Cook Time35 mins
Total Time55 mins
Course: Dessert
Cuisine: American
Keyword: brookie, Brownie, brownies, chocolate chip cookies, cookie dough, Cookies, Marshmallows
Servings: 16

Ingredients

For Cookie Dough:

  • 1 stick (113 grams) unsalted butter cold and cubed
  • 1/2 cup (107 grams) brown sugar packed
  • 1/4 cup plus 1 tablespoon (62 grams) granulated sugar
  • 1 large egg
  • 1 teaspoon vanilla extract
  • 1 3/8 cup (165 grams) flour
  • 1/2 teaspoon cornstarch
  • 1/4 teaspoon baking soda
  • 1/4 teaspoon baking powder
  • 1/2 teaspoon salt
  • 6 ounces (1/2 bag) mini chocolate chips

For Brownie Batter:

  • 1 stick (113 grams) unsalted butter melted and cooled
  • 1 tablespoon vegetable oil
  • 1/2 cup plus 1 tablespoon (120 grams) brown sugar packed
  • 1/2 cup plus 1 tablespoon (111 grams) granulated sugar
  • 2 large eggs
  • 2/3 cup (80 grams) flour
  • 3/8 cup (31 grams) unsweetened cocoa powder
  • 1 teaspoon salt

For Marshmallows:

  • 1/2 recipe Marshmallows OR
  • 1/2 package mini marshmallows

Instructions

For Cookie Dough:

  • Preheat oven to 350 degrees (F). Spray a 9x8 pan with non-stick spray and line with parchment paper, leave an overhang to make it easy to remove the baked brookies.
  • Using a hand mixer or a stand mixer, mix the cold butter, brown sugar, and granulated sugar. Beat for 4 minutes.
  • Add the eggs and vanilla. Beat for 1 minute.
  • Fold in the flour, cornstarch, baking soda, baking powder, and salt. Mix until just combined.
  • Fold in the mini chocolate chips.
  • Break chunks of cookie dough off and place them in the bottom of the pan. The chunks should be about 1/2 to 1 inch. Repeat until there are only small gaps without cookie dough.
  • Allow the dough to chill while you make the brownie batter.

For Brownie Batter:

  • In a large bowl, combine the melted and cooled butter, oil, and both types of sugar. Whisk until well combined.
  • Add the eggs, vanilla, and salt and whisk until fully combined and light in color.
  • Sift in the flour and cocoa powder and gently fold together. Only fold until just combined.
  • Pour the batter over the cookie dough.

For Marshmallows:

  • If using homemade marshmallows, cut the marshmallows into smaller chunks.
  • Spread the marshmallows over the top until most of the brownie batter is covered.
  • Bake for 35-40 minutes until a toothpick inserted in the center comes out with only a few moist crumbs.
  • Allow to cool completely. Lift brookies from pan and cut into 16 squares