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.

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!
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.
How to make Marshmallow Brookies
Chocolate Chip Cookie Layer
STEP 1: Preheat oven to 350 degrees (F). Spray an 8x8 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.
The butter, sugar, vanilla, and eggs combined in a bowl The dry ingredients combined in a bowl.
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.
STEP 7: Break chunks of cookie dough off and place them in the bottom of the pan. The chunks should be about ½ 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.
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.
The wet ingredients combined in a bowl The dry ingredients combined in a bowl.
STEP 4: Add the dry ingredients to the wet ingredients. Mix until just combined.
STEP 5: Fold the chocolate into the mixture.
STEP 6: Pour the brownie batter over the chilled cookie dough.
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.
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.
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.
More Bar Recipes from Kitchen 335
- Banana Pudding Cheesecake Bars- a nilla wafer crust and a creamy banana flavored cheesecake.
- Apple Crumble Bars- shortbread crust, a tart apple filling, and a sweet crumble topping.
- Cookies and Cream Bars- the perfect crinkly top and gooey center packed full of crushed oreo cookies.
- Fudgy Brownies- the best homemade brownie recipe. They are loaded with melty chocolate and perfectly gooey.
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Recipe originally posted October 2019.
Recipe
Marshmallow Brookies
Ingredients
For Chocolate Chip Cookie Layer:
- 6 tablespoons (85 grams) unsalted butter softened
- ½ cup (107 grams) brown sugar packed
- ½ cup (99 grams) granulated sugar
- 1 large egg
- 1 teaspoon vanilla extract
- 1 ½ cup (180 grams) all-purpose flour
- ½ teaspoon baking soda
- ½ teaspoon baking powder
- ½ teaspoon salt
- ¾ cup (127 grams) chocolate chopped or chocolate chips
For Brownie Layer:
- 12 tablespoons (170 grams) unsalted butter melted and cooled
- 1 ¼ cup (266 grams) brown sugar packed
- 2 large eggs
- 2 teaspoons vanilla extract
- ¾ cup (90 grams) all-purpose flour
- ½ cup (42 grams) cocoa powder
- 1 teaspoon salt
- ¾ 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 8x8 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 ½ 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
Monica says
THiS recipe was sooooo good! I tried it warm when it was just made and wasn't a fan of it. Once it was cold... game changer!!! I legit need to stop myself from eating the whole thing. 20/10 would recommend