The Ultimate Gooey S’mores Cookie Bars Recipe: Campfire Flavor in Your Oven

There is something inherently nostalgic about the combination of toasted marshmallows, melting chocolate, and crunchy graham crackers. It evokes memories of crackling campfires, starry nights, and sticky fingers. However, you don’t need a tent, a fire pit, or the great outdoors to enjoy this classic treat. Enter the S’mores Cookie Bars—a decadent, gooey, and utterly irresistible dessert that brings the magic of the campfire right into your kitchen. These bars are thicker, softer, and arguably messier in the best way possible than their traditional counterparts, offering a perfect ratio of buttery graham cookie dough to molten chocolate and marshmallow filling.

If you have been searching for the perfect crowd-pleasing dessert that requires zero roasting skills and delivers maximum flavor, this is it. These bars are designed to be dense and chewy, with a “wet” and glossy interior that stays soft even after cooling. Whether you are baking for a summer barbecue, a cozy winter gathering, or just a Tuesday night craving, this guide will walk you through every step to ensure your bars come out golden, gooey, and glistening with deliciousness every single time.

Why You Will Love This Recipe

While traditional s’mores are delicious, they are also fleeting. You have about thirty seconds to eat one before the chocolate hardens again or the marshmallow slides off. S’mores Cookie Bars solve the structural integrity issues of the original while amplifying the flavor profile. Here is why this recipe is about to become a staple in your baking rotation:

• No Campfire Required: Achieve that signature smoky-sweet flavor using your oven. It is weather-proof baking at its finest.
• Feeds a Crowd: Unlike roasting marshmallows one by one, a single pan of these bars yields 16 to 24 generous servings, making them perfect for potlucks and parties.
• Texture Heaven: You get the crunch of graham crackers incorporated directly into a soft cookie dough, the snap of chocolate, and the stretch of marshmallow all in one bite.
• Customizable: Whether you prefer dark chocolate, milk chocolate, or want to add a swirl of peanut butter, this sturdy base recipe welcomes variation.

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Ingredients

The secret to the best S’mores Cookie Bars lies in the quality of the ingredients and the ratio of the layers. We use a graham cracker-infused cookie dough to sandwich a generous layer of chocolate and marshmallow crème. Using marshmallow crème (or fluff) instead of standard marshmallows ensures the filling stays gooey and doesn’t disappear into the dough during baking.

For the Graham Cookie Dough

• Unsalted Butter – 1 cup (2 sticks), softened to room temperature. This provides the rich, buttery base necessary for a soft cookie.
• Light Brown Sugar – 1 cup, packed. Brown sugar adds moisture and that deep caramel flavor that pairs perfectly with graham crackers.
• Granulated White Sugar – ½ cup. This helps create slightly crisp edges on the bars.
• Eggs – 2 large eggs, room temperature. They bind the dough together and add richness.
• Vanilla Extract – 2 teaspoons. Essential for enhancing the flavor of the chocolate and graham crackers.
• All-Purpose Flour – 2 ½ cups. The structural backbone of your cookie bars.
• Graham Cracker Crumbs – 1 ½ cups (about 10-12 full sheets crushed). This is the game-changer that infuses the entire dough with s’mores flavor.
• Baking Powder – 1 teaspoon. Gives the bars a little lift so they aren’t too dense.
• Salt – ½ teaspoon. Balances the extreme sweetness of the marshmallow and chocolate.

For the Gooey Filling

• Semi-Sweet or Milk Chocolate Chips – 2 cups (or 3-4 full-sized chocolate bars). Milk chocolate is traditional for s’mores, but semi-sweet balances the sugar better.
• Marshmallow Crème / Fluff – 1 jar (7 oz). This creates a reliable, glossy layer that remains soft. If you only have regular marshmallows, see the “Tips” section below.

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Instructions

Follow these step-by-step instructions to create the ultimate layered dessert. Precision in layering is key to getting that glossy, “food porn” style cross-section when you cut them.

Step 1: Preparation

Preheat your oven to 350°F (175°C). Line a 9×13 inch baking pan with parchment paper or aluminum foil, leaving an overhang on the sides. This “sling” will allow you to lift the entire block of bars out of the pan for clean cutting later. Spray the lining lightly with non-stick cooking spray.

Step 2: Mix the Dry Ingredients

In a medium mixing bowl, whisk together the all-purpose flour, graham cracker crumbs, baking powder, and salt. Ensure the graham cracker crumbs are fine; large chunks can make the dough crumbly. Set this bowl aside.

Step 3: Cream the Butter and Sugars

In a large bowl or the bowl of a stand mixer fitted with the paddle attachment, beat the softened butter, brown sugar, and granulated sugar together on medium-high speed. You want the mixture to be light, creamy, and pale in color, which usually takes about 2-3 minutes. Scrape down the sides of the bowl as needed.

Step 4: Add Wet Ingredients

Reduce the mixer speed to low and add the eggs one at a time, mixing well after each addition. Pour in the vanilla extract. Mix until combined, but be careful not to over-beat at this stage.

Step 5: Combine Dough

Gradually add the dry flour and graham mixture to the wet ingredients. Mix on low speed just until the flour streaks disappear. The dough will be thick and slightly sticky. It should smell intensely of graham crackers and vanilla.

Step 6: Create the Base Layer

Take about two-thirds (2/3) of the cookie dough and press it evenly into the bottom of your prepared baking pan. You can use the bottom of a measuring cup or your hands (lightly floured) to press it down firmly to create a solid crust.

Step 7: The Chocolate Layer

Sprinkle the chocolate chips (or lay down chocolate bar rectangles) evenly over the bottom crust. Try to cover as much surface area as possible so every bite has chocolate.

Step 8: The Marshmallow Layer

This is the tricky (and sticky) part. Dollop spoonfuls of the marshmallow crème over the chocolate layer. It does not need to be a perfect even layer as it will spread in the oven. If you try to spread it with a knife, it will drag the chocolate with it. Just drop blobs all over the chocolate.

Step 9: The Top Crust

Take the remaining one-third of the cookie dough. Flatten small pieces of it between your hands into shingles or discs and place them over the marshmallow layer. It is okay—and actually preferred—if there are gaps where the marshmallow and chocolate peek through. This creates that beautiful, rustic, bubbling look when baked.

Step 10: Bake and Cool

Bake in the preheated oven for 25 to 30 minutes. The top should be golden brown, and the marshmallow peeking through should be toasted. Do not overbake, or the bars will become dry. Remove from the oven and place the pan on a wire rack. Crucial Step: Let them cool completely (at least 2-3 hours) before cutting. The filling is liquid lava when hot and needs time to set.

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Tips for Success

The Marshmallow Dilemma:
Many bakers ask if they can use regular marshmallows instead of fluff. You can, but standard marshmallows tend to dissolve completely or become chewy and rubbery when baked for this long. Marshmallow crème contains stabilizers that keep it creamy. If you must use regular marshmallows, cut them in half and press them tightly into the chocolate layer, but expect a chewier, less creamy result.

Cutting Clean Bars:
S’mores bars are notoriously sticky. To get clean cuts, chill the bars in the refrigerator for an hour after they have cooled to room temperature. Lift them out using the parchment overhang, place on a cutting board, and use a large sharp knife. Wipe the knife with a warm, damp cloth between cuts to prevent the marshmallow from dragging.

Intensifying the Flavor:
For a more “adult” flavor profile, brown the butter before mixing it with the sugar. Brown butter adds a nutty, toasted aroma that complements the graham crackers beautifully. Just be sure to let the brown butter solidify back to a softened state before creaming.

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Variations to Try

Once you have mastered the classic, try these twists to keep things exciting:

• Peanut Butter S’mores: Swirl ½ cup of creamy peanut butter into the marshmallow fluff layer or use peanut butter cups instead of plain chocolate bars.
• Nutella S’mores: Replace the chocolate bars with a generous drizzle of hazelnut spread.
• Salted Caramel: Drizzle salted caramel sauce over the chocolate layer before adding the marshmallow. Sprinkling flaky sea salt on top of the bars right after they come out of the oven cuts the sweetness.
• Double Chocolate: Add ¼ cup of cocoa powder to the dough mixture for a chocolate graham base.

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Storage and Freezing

Room Temperature:
Store these bars in an airtight container at room temperature for up to 4 days. If you stack them, place a sheet of parchment paper or wax paper between layers to stop the marshmallow from sticking everything together.

Freezing:
These bars freeze surprisingly well. Cut them into squares, wrap each one individually in plastic wrap, and store them in a freezer-safe bag for up to 3 months. Thaw on the counter for an hour before eating. You can also microwave a thawed bar for 10-15 seconds to revive that “fresh out of the oven” gooey texture.

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The Science of the S’more

Why do these flavors work so well together? It is a study in texture and taste contrast. The graham cracker provides a dry, brittle crunch and a slight savoriness that cuts through the sugar. The chocolate provides the melting point—the fat that coats the tongue. The marshmallow provides the sweet, aerated elasticity. When you bake these into a bar, the cookie dough acts as a sponge, absorbing some of the butter and chocolate, creating a hybrid texture that is neither fully cookie nor fully cake, but a delicious fudge-like brownie consistency. It is comfort food engineering at its finest.

Enjoy baking these S’mores Cookie Bars! They are a testament to the fact that you don’t need fancy equipment to create a bakery-worthy dessert—just a love for chocolate, marshmallow, and a little bit of patience while they cool.