These Marshmallow Brookies have a layer of chocolate cookie, a layer of fudgy brownie, and a layer of toasted marshmallows. They are the perfect fusion of three delicious desserts.

A closeup of a marshmallow brookie in a pan

If you asked me to choose between a warm chocolate chip cookie, a fudgy brownie, or a perfectly toasted marshmallow I would be hard-pressed to make a choice. Roll all three of those together and you have basically created a dream dessert!

The name brookie comes from the combination of brownies and cookies in this recipe, in case you hadn’t picked up on that already. I made each of these layers individually, but you could also pick up some premade cookie dough, a box of brownie mix, and some marshmallows and call it a day. You can go wrong with this combination, homemade or not!

A straight on shot of a brookie

Ingredients for Marshmallow Brookies:

Ingredients for Chocolate Chip Cookie Layer:

  • Unsalted butter. I always make sure to use unsalted butter when baking because there is no “standard” for the amount of salt they can add to butter. So if you add salt to a recipe and then use salted butter you could end up with a very salty end product.
  • Granulated Sugar. This will sweeten the cookie dough and make it chewier.
  • Brown sugar. Brown sugar adds a softer texture to the finished product.
  • Eggs. It will be easier to incorporate the eggs into the batter if they are at room temperature.
  • Vanilla extract. Vanilla is a must in baked goods just like salt. Real vanilla adds a better flavor than imitation vanilla.
  • All-purpose flour. Measuring the flour correctly is very important. I suggest weighing your flour out (I use this scale). If you want to use a measuring cup, make sure you spoon the flour into the cup and level it off with a knife. Don’t use the cup to scoop directly from the flour.
  • Baking soda. This will help the cookies to rise.
  • Baking powder. This will also help the cookies to rise.
  • Salt. Salt is a must in baked goods. It will help to balance out the sweetness and improve the overall flavor.
  • Chocolate, chopped, or chocolate chips. I prefer semi-sweet chocolate, but you can use whatever you prefer.

Ingredients for Fudgy Brownie Layer:

  • Unsalted Butter. See above note.
  • Brown Sugar. See above note.
  • Eggs. See above note.
  • Vanilla Extract. See above note.
  • All-purpose Flour. See above note.
  • Cocoa Powder. This adds to the chocolatey flavor of the brownies.
  • Salt. See above note.
  • Chocolate. See above note.

Ingredients for Toasted Marshmallow Layer:

  • Mini Marshmallows. You can also use regular sized marshmallows if you already have them on hand.
All of the ingredients needed for this recipe

How to make Marshmallow Brookies

STEP 1: Preheat oven to 350 degrees (F). Spray an 8×8 pan with non-stick spray and line with parchment paper, leave an overhang to make it easy to remove the baked brookies.

STEP 2: In a large bowl using a hand mixer or in the bowl of a stand mixer cream together the butter, granulated sugar, and brown sugar until light and fluffy.

STEP 2: Add the eggs one at a time, mixing fully before adding the next. Pour in the vanilla and combine.

STEP 4: In a medium bowl combine the flour, baking soda, baking powder, and salt. Whisk to combine.

STEP 5: Add the dry ingredients to the wet ingredients and mix until just combined. Be sure not to over mix.

STEP 6: Fold in the chocolate chips or the chopped chocolate.

The completed cookie dough in a bowl

STEP 7: 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.

STEP 8: Allow the dough to chill while you make the brownie batter.

The cookie dough broken into chunks and placed in the prepared pan

Fudgy Brownie Layer

STEP 1: In a medium bowl mix with a hand mixer combine the melted butter and brown sugar. When fully combined add the eggs and vanilla. Beat until fully combined and light in color.

STEP 2: In a small bowl combine the flour, cocoa powder, and salt. Whisk to combine and remove any lumps.

STEP 4: Add the dry ingredients to the wet ingredients. Mix until just combined.

STEP 5: Fold the chocolate into the mixture.

The completed brownie batter in a bowl

STEP 6: Pour the brownie batter over the chilled cookie dough.

The brownie batter poured over the cookie dough in the prepared pan

Toasted Marshmallow Layer

STEP 1: Sprinkle the mini marshmallows over the top of the brookies until almost all of the brownie batter is covered. The marshmallows will spread while baking. If you are using regular-sized marshmallows I recommend cutting them up.

Mini marshmallows sprinkled on top of the brownie batter

STEP 2: Bake for 35-40 minutes or until a toothpick inserted in the center comes out with only a few moist crumbs.

STEP 3: Allow to cool completely in pan. Lift the Marshmallow Brookies out of the pan and cut into 16 squares.

A stack of marshmallow brookies. One has a bite out of it

More Bar Recipes

  • Snickers Cookie Bars– These bars have a shortbread base topped with a caramel and peanut mixture and a layer of chocolate.
  • No-Bake S’mores Bars– Golden graham cereal, marshmallows, and chocolate chips are combined to make these yummy bars.
  • Rhubarb Bars– A shortbread crust topped with a rhubarb custard.
  • Glazed Cherry Bars– A cookie base with a cherry pie filling and chunks of cookie on top.
Two brookies stacked on top of each other

More Bar Recipes from Kitchen 335

A close up of a marshmallow brookie with a bite out of it

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Recipe originally posted October 2019.

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5 from 3 votes

Marshmallow Brookies

These Marshmallow Brookies have a layer of chocolate cookie, a layer of fudgy brownie, and a layer of 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, marshmallow brookies, Marshmallows
Servings: 16
Calories: 300kcal

Ingredients

For Chocolate Chip Cookie Layer:

  • 6 tablespoons (85 grams) unsalted butter softened
  • 1/2 cup (107 grams) brown sugar packed
  • 1/2 cup (99 grams) granulated sugar
  • 1 large egg
  • 1 teaspoon vanilla extract
  • 1 1/2 cup (180 grams) all-purpose flour
  • 1/2 teaspoon baking soda
  • 1/2 teaspoon baking powder
  • 1/2 teaspoon salt
  • 3/4 cup (127 grams) chocolate chopped or chocolate chips

For Brownie Layer:

  • 12 tablespoons (170 grams) unsalted butter melted and cooled
  • 1 1/4 cup (266 grams) brown sugar packed
  • 2 large eggs
  • 2 teaspoons vanilla extract
  • 3/4 cup (90 grams) all-purpose flour
  • 1/2 cup (42 grams) cocoa powder
  • 1 teaspoon salt
  • 3/4 cup (127 grams) chocolate chopped or chocolate chips

For Marshmallow Layer:

  • 2 cups mini marshmallows

Instructions

For Chocolate Chip Cookie Layer:

  • Preheat oven to 350 degrees (F). Spray an 8×8 pan with non-stick spray and line with parchment paper, leave an overhang to make it easy to remove the baked brookies.
  • In a large bowl using a hand mixer or in the bowl of a stand mixer cream together the butter, granulated sugar, and brown sugar until light and fluffy.
  • Add the eggs one at a time, mixing fully before adding the next. Add the vanilla and combine.
  • In a medium bowl combine the flour, baking soda, baking powder, and salt. Whisk to combine.
  • Add the dry ingredients to the wet ingredients. Mix until just combined.
  • Fold in the chocolate.
  • 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 medium bowl mix with a hand mixer combine the melted butter and brown sugar. When fully combined add the eggs and vanilla. Beat until fully combined and light in color.
  • In a small bowl combine the flour, cocoa powder, and salt. Whisk to combine and remove any lumps.
  • Add the dry ingredients to the wet ingredients and mix until just combined.
  • Fold the chocolate into the batter.
  • Pour the brownie batter over the cookie dough.

For Marshmallow Layer:

  • Sprinkle the mini 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

Nutrition

Serving: 1brookie | Calories: 300kcal | Carbohydrates: 41.5g | Protein: 4.7g | Fat: 14.2g | Saturated Fat: 8.6g | Cholesterol: 69mg | Sodium: 283mg | Potassium: 137mg | Fiber: 1.4g | Sugar: 25.5g | Calcium: 31mg | Iron: 2mg
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