A buttery graham cracker crust, rich fudgy brownies, fluffy marshmallow frosting, and toasted marshmallows combine in these irresistible s’mores brownies. They capture the flavors of the classic campfire treat in a single, shareable dessert bar that’s simple to make and perfect for gatherings.
If you love s’mores, these brownies deserve a place on your baking list. They layer a buttery graham cracker crust, a deeply chocolatey fudgy brownie, and a cloud-like marshmallow frosting for a nostalgic, indulgent dessert. Rather than building individual s’mores around a campfire, all the flavors are layered and baked in one 9-inch square pan so they’re easy to slice and share.
The brownie layer uses a combination of semisweet and bittersweet chocolate to achieve a rich chocolate flavor that’s not overly sweet. Natural cocoa powder adds depth and fudgy texture, and chopped milk chocolate folded into the batter gives pockets of melty chocolate throughout. A marshmallow-flavored frosting made with marshmallow creme and confectioners’ sugar tops the cooled brownies, and toasted mini marshmallows, plus extra chopped chocolate and graham cracker pieces, finish the bars with the classic s’mores look and taste.
Why You’ll Love These S’mores Brownies
- All the classic s’mores flavors together. The graham crust, chocolatey brownie, and marshmallow frosting recreate that favorite campfire treat in bar form.
- Fudgy, chocolate-forward brownies. A blend of melted chocolate and cocoa yields a dense, fudgy crumb that balances the sweet frosting.
- Easy to serve and share. Baked in a 9-inch square pan, the bars are ideal for potlucks, cookouts, and parties.
- Simple finishing touches. Toasted mini marshmallows, chopped milk chocolate, and graham cracker crumbs make the presentation special without extra fuss.
- No campfire required. Enjoy nostalgic s’mores flavors any time from your kitchen.
Key Ingredients
- Graham cracker crumbs – Form the buttery crust that delivers the classic s’mores base. You’ll need roughly 10 full sheets to make 1½ cups (about 150 g) of crumbs.
- Chocolate – Use a mix of semisweet and bittersweet for depth, plus chopped milk chocolate folded into the batter and sprinkled on top for authentic s’mores notes.
- Natural cocoa powder – Adds chocolate intensity and helps create a dense, fudgy texture.
- Marshmallow creme – The base for the marshmallow frosting that gives the topping its classic sweet, pillowy flavor.
- Mini marshmallows – Toast separately and use as a garnish so they keep their toasted exterior without melting the frosting.
How to Make S’mores Brownies
Prepare the crust.
Combine graham cracker crumbs, granulated sugar, a pinch of salt, and melted unsalted butter until fully moistened. Press the mixture firmly into a parchment-lined 9-inch square pan and bake briefly so the crust sets and crisps slightly. Allow it to cool while you make the brownie batter.
Make the brownie batter.
Melt butter with the semisweet and bittersweet chocolate until smooth, then let the mixture cool until warm but not hot. Whisk in granulated and brown sugars until incorporated. Add eggs one at a time, whisking well after each addition, then stir in vanilla. Fold in all-purpose flour, unsweetened cocoa powder, and salt just until combined; a few streaks of flour are okay. Fold in chopped milk chocolate for melty pockets in the baked bars.
Bake.
Spread the batter evenly over the partially baked crust and bake until the edges are set, the top is glossy, and a toothpick inserted near the center comes out with a few moist crumbs. Slightly under-baking helps keep the center fudgy. Cool the brownies completely before adding the frosting.
Make the marshmallow frosting.
Beat softened butter until creamy, then add marshmallow creme, confectioners’ sugar, vanilla, and a pinch of salt. Mix until the frosting is light, fluffy, and spreadable. If the frosting is too stiff, add 1 to 2 teaspoons of milk or cream, a little at a time, until it spreads easily while still holding soft swoops. Spread the frosting over the cooled brownies.
Garnish.
Top the frosted brownies with toasted mini marshmallows, chopped milk chocolate, and graham cracker crumbs or pieces. For best results, toast the mini marshmallows separately under the broiler or with a handheld torch and let them cool for a minute before placing on the frosting to prevent it from melting.
Tips for Success
- Cool the chocolate slightly. Let the melted butter and chocolate cool until warm to the touch before adding eggs so they don’t scramble and the batter stays smooth.
- Mix gently once flour is added. Over-mixing after adding the dry ingredients can make brownies tough; stir just until no large dry streaks remain.
- Avoid over-baking. Begin checking a few minutes before the minimum time. The edges should be set and the center slightly underdone for fudgy brownies.
- Cool completely before frosting. Even slightly warm brownies will soften the marshmallow frosting and make it harder to spread neatly.
- Toast marshmallows separately. Broiling or torching mini marshmallows before garnishing gives the desired toasted flavor without melting the frosting.
- Choose quality chocolate. Using a mix of semisweet and bittersweet chocolate provides balanced depth; for a sweeter result, use only semisweet.
How to Store
Room temperature: Store in an airtight container for up to 2 days.
Refrigerator: Keep in an airtight container for up to 5 days. Allow 15–20 minutes at room temperature before serving so the frosting softens.
Freezer: Freeze unfrosted brownies for up to 3 months. Wrap tightly in plastic wrap and foil or use a freezer-safe container. Thaw in the refrigerator or at room temperature before frosting and garnishing.
Make-ahead: Bake the brownies a day ahead, cool completely, then cover. Frost and garnish just before serving for the best texture and presentation.
Bring a Little Campfire Magic to Your Kitchen
These s’mores brownies compress everything you love about classic s’mores into one delicious dessert bar. With a crunchy graham crust, fudgy brownie layer, pillowy marshmallow frosting, and toasted mini marshmallows on top, they’re ideal for summer cookouts, parties, or anytime you want a nostalgic treat. Follow the tips above for clean slices and the best texture, and enjoy sharing a dessert that’s both playful and indulgent.
S’mores Brownies
Ingredients
For the crust:
- 1 ½ cups (150 g) graham cracker crumbs, about 10 sheets
- 2 tablespoons (25 g) granulated sugar
- pinch of salt
- 6 tablespoons (85 g) unsalted butter, melted
For the brownies:
- ¾ cup (170 g) unsalted butter
- 3 ounces (85 g) semisweet chocolate, roughly chopped
- 3 ounces (85 g) bittersweet chocolate, roughly chopped
- 1 ¼ cups (250 g) granulated sugar
- ½ cup (100 g) firmly packed light brown sugar
- 3 large eggs
- 2 teaspoons vanilla extract
- ¾ cup (90 g) all-purpose flour
- ¼ cup (21 g) unsweetened natural cocoa powder
- ½ teaspoon salt
- 1 cup (140 g) chopped milk chocolate
For the frosting:
- ½ cup (113 g) unsalted butter, softened
- 1 cup (about 100 g) marshmallow creme
- 1 ¼ cups (138 g) confectioners’ sugar
- 1 teaspoon vanilla extract
- pinch of salt
- 1–2 teaspoons milk or cream, if needed
- toasted mini marshmallows, extra milk chocolate, and graham cracker pieces or crumbs for garnish
Instructions
To make the crust:
- Preheat the oven to 350°F (175°C). Lightly grease and line a 9-inch square baking pan with parchment paper.
- Combine the graham cracker crumbs, sugar, and salt. Stir in the melted butter until evenly moistened.
- Press the mixture firmly into the prepared pan and bake for 8 minutes. Set aside to cool slightly while you make the brownie batter.
To make the brownies:
- Place the butter, semisweet chocolate, and bittersweet chocolate in a heatproof bowl. Melt gently—either in short bursts in the microwave at reduced power or using a double boiler—stirring until smooth. Allow to cool until warm but not hot.
- Add the granulated and brown sugars to the chocolate mixture and whisk to combine.
- Whisk in the eggs one at a time, mixing well after each addition. Stir in the vanilla.
- Fold in the flour, cocoa powder, and salt just until combined; a few flour streaks are fine.
- Fold in the chopped milk chocolate.
- Spread the batter over the partially baked crust.
- Bake 32 to 38 minutes, or until the edges are set, the top is glossy, and a pick inserted near the center comes out with a few moist crumbs.
- Cool completely before frosting.
To make the frosting and finish:
- Beat the softened butter with an electric mixer on medium speed until creamy.
- Add the marshmallow creme, confectioners’ sugar, vanilla, and salt. Mix until the frosting is smooth, fluffy, and easily spreadable. Add 1–2 teaspoons of milk or cream if it’s too stiff.
- Spread the frosting over the cooled brownies, making soft swoops for texture.
- Garnish with toasted mini marshmallows, chopped milk chocolate, and graham cracker pieces. Chill briefly if you want cleaner slices, then cut and serve.
Notes
- Allow the brownies to cool completely before frosting to keep the topping stable.
- Toast the mini marshmallows separately so they develop a char without melting the frosting; let them cool a minute before placing them on the bars.
- For clean slices, chill the frosted brownies 20–30 minutes and wipe the knife clean between cuts.
- Storage: Room temperature up to 2 days in an airtight container; refrigerated up to 5 days. Freeze unfrosted for up to 3 months.