These s’mores cookie bars with marshmallow frosting are the kind of easy summer dessert that delivers all the nostalgic flavor of a classic campfire s’more without needing a fire pit. They start with a soft graham cracker cookie dough, are filled with a thick layer of melty chocolate, and finish with a plush marshmallow creme frosting that sets just enough for clean slices.
The cookie base is buttery, chewy, and full of finely ground graham cracker crumbs, giving each bite that familiar honey-graham flavor. The chocolate filling bakes into the center like a rich, fudgy layer, while the marshmallow topping adds the sweet, creamy finish that makes these bars feel like a true s’mores dessert.
This recipe is simple enough for casual baking but impressive enough to bring to a cookout, potluck, birthday party, or weekend gathering. Because the bars are baked in an 8×8 pan and cut into squares, they are easy to transport, serve, and share. If you love gooey chocolate desserts, soft cookie bars, and marshmallow frosting, these s’mores bars are a must-bake.
How to Make Them
1
Make the graham cracker cookie dough. Cream the butter and powdered sugar, then mix in the egg and vanilla before adding the flour, graham cracker crumbs, and salt. The dough should be soft, buttery, and easy to spread.
2
Shape the first cookie layer. Spread half of the dough into a parchment-lined 8×8 baking pan. Lift the parchment out carefully and transfer the dough layer to a flat plate or cutting board that can fit in the refrigerator.
3
Prepare the bottom layer. Line the pan again with parchment paper and spread the remaining dough evenly into the bottom. Chill both cookie dough layers for 30 minutes so they are easier to handle and bake evenly.
4
Make the chocolate filling. Melt the chocolate chips with butter until smooth, then whisk in the remaining ingredients. The finished filling should be glossy, thick, and similar in texture to brownie batter.
5
Spread the chocolate filling. Pour the chocolate mixture over the chilled cookie dough layer in the pan. Use a spatula to smooth it from edge to edge so every bar has a generous chocolate center.
6
Add the top cookie layer. Remove the chilled dough from the refrigerator, peel away the parchment, and place it upside down over the chocolate filling. The flat side should face up for a smoother finished surface.
7
Bake the s’mores cookie bars. Bake until the edges are golden brown and the top is puffed and set. The center should look soft and matte, not wet or shiny.
8
Cool, frost, and slice. Let the bars cool completely before adding the marshmallow frosting. Once the frosting has set, cut the dessert into 15 squares with a sharp knife. For neat slices, warm the knife under hot water and wipe it clean between cuts.
These s’mores bars are rich, gooey, and made for anyone who loves the combination of graham crackers, chocolate, and marshmallow. They taste like a campfire dessert but are easy to make in the kitchen, making them a reliable treat for summer parties or anytime a s’mores craving hits.
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S’mores Cookie Bars with Marshmallow Frosting
Equipment
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square 8×8 metal baking pan
Ingredients
Graham Cracker Cookie Crust
- 1 cup unsalted butter, room temperature
- 1 1/4 cups powdered sugar
- 1 large egg, room temperature
- 1 teaspoon vanilla paste or extract
- 1 1/2 cups all-purpose flour, measured properly
- 1 cup finely ground graham cracker crumbs
- 1/2 teaspoon fine sea salt
Chocolate Filling
- 3/4 cup dark or semi-sweet chocolate chips
- 1/4 cup unsalted butter
- 1 large egg
- 1/4 cup packed brown sugar
- 1 teaspoon vanilla
- 1 tablespoon cocoa powder
- 1/4 teaspoon fine sea salt
Marshmallow Frosting
- 3.5 ounces marshmallow creme
- 1.5 ounces cream cheese, softened
- 1/4 cup heavy cream
- 1 teaspoon vanilla paste
- Graham cracker crumbs, for topping
Instructions
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Line an 8×8 metal baking pan with parchment paper so it covers all four sides. Set the pan aside.
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In the bowl of a stand mixer, or in a large bowl with a hand mixer, cream the room-temperature butter and powdered sugar together until combined. Start slowly so the powdered sugar does not spill out of the bowl.
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Mix in the egg and vanilla until smooth. Add the flour, graham cracker crumbs, and salt, then mix just until a soft dough forms.
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Divide the dough in half. Spread one portion evenly into the prepared pan, then lift it out using the parchment and place it on a flat plate or cutting board. Line the pan again and spread the remaining dough evenly into the bottom. Chill both dough layers in the refrigerator for 30 minutes.
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While the dough chills, preheat the oven to 325°F.
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Make the chocolate filling. Melt the chocolate chips and butter together until smooth. Whisk in the egg, brown sugar, and vanilla, then whisk in the cocoa powder and salt until the filling is thick and glossy.
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Remove both chilled cookie dough layers from the refrigerator. Pour the chocolate filling over the dough layer in the pan and spread it evenly. Peel the parchment from the second dough layer and place it upside down over the chocolate filling, with the flat side facing up.
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Bake for 40–45 minutes, or until the top is puffy and the edges are golden brown. The center may look slightly blotchy, which is normal. Cool the bars in the pan on a wire rack for 2–3 hours, or until completely cool.
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Make the marshmallow frosting by stirring the marshmallow creme and softened cream cheese together in a medium bowl until smooth. Whisk in the heavy cream and vanilla paste until creamy.
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Spread the marshmallow frosting over the cooled s’mores cookie bars. Let the frosting set for about 30 minutes, then sprinkle with extra graham cracker crumbs if desired.
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Use a sharp knife to cut the dessert into 15 bars. For cleaner cuts, run the knife under hot water and wipe it dry between slices.
Notes
Storage: Store leftover s’mores cookie bars in an airtight container at room temperature for 3–4 days.
The calorie information provided for this recipe is an estimate and is not guaranteed.
This recipe was created and tested by a real person
Recipes work best when they are carefully tested, measured, and written with real baking experience. These s’mores cookie bars were developed to have a soft graham cracker crust, a gooey chocolate center, and a marshmallow frosting that slices cleanly after setting.