S’Mores Cookie Bars: A Gooey Layered Treat for Any Occasion

By:

Sage Martinez

Published:

October 3, 2026

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If you have ever wanted that campfire pull without the smoke in your hair, these bars deliver it in one slice, gooey center and all.

S’mores cookie bars take everything you love about a s’more and bake it into a bar you can stack, pack in a lunch, and share on a platter.

Two layers of graham cracker cookie dough hold a full layer of Hershey’s chocolate bars and a thick spread of marshmallow fluff in the middle.

There is no fire pit involved here. No skewers to hunt down, no marshmallows dropping into the coals, and no weather excuses. You need an 8×8 inch pan and a preheated oven, and the whole thing is done in under an hour.

What makes these bars worth baking is the texture. The graham cracker cookie dough is soft and chewy instead of dry and crumbly. The chocolate actually melts into the dough.

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The marshmallow fluff stays gooey, so the center pulls like taffy every time you slice in. You get the crunchy edge, the gooey middle, and that unmistakable graham, chocolate, and marshmallow flavor, all from a single pan.

The recipe comes from Chahinez Tabet Aoul, who shares it on the Lifestyle of a Foodie blog. Her starting point was simple. S’more cravings kept showing up at inconvenient moments.

The middle of winter. A random Tuesday in February. Ten at night while already in bed.

She wanted the layers, the contrast, and the nostalgia in something bakeable in under an hour, and this is the result. If you want to see the source for yourself, the original s’mores cookie bars recipe is worth a look.

Because the bars hold together, they travel well. Wrap them for a picnic, tuck one into a lunchbox, or slice them into neat squares for a party tray. The cross section is clean enough for photos and sturdy enough for gifting, which is not something you can say about a s’more eaten off a stick.

Jump to:

Here is the short version of why this recipe earns a permanent spot in the rotation.

Year round s’mores. An 8×8 inch pan and a preheated oven are all you need. No campfire, no coals, no wind.
Graham cracker cookie dough on both the top and the bottom. Every bite tastes like a real s’more instead of a plain cookie bar.
A thick, gooey marshmallow layer. Marshmallow fluff does the work here, not mini marshmallows, so the center stays soft and stretchy.
A clean slice. The bars cut into a neat cross section that looks gorgeous on a plate, which makes them easy to gift, serve at parties, or photograph.

Ingredients You’ll Need

Full measurements are in the recipe card below.

The notes here explain what each ingredient does, so you know which swaps are safe and which ones will change the bar.

1/2 cup butter, softened. Salted or unsalted both work. If you use unsalted butter, do not skip the added salt.
1/3 cup brown sugar. This is where the chew and the molasses depth come from.
1/4 cup granulated sugar. This is what gives you crisp edges.
1 large egg. It binds the dough.
1 teaspoon vanilla extract. A full teaspoon. Do not skimp here.
1 1/2 cups all purpose flour. Spoon it into the cup and level it off, or better, weigh it.
1/2 cup finely crushed graham crackers, about 3.5 full sheets. This is what makes the dough taste like s’mores instead of plain cookie dough, so do not skip it or substitute it.
3/4 teaspoon baking soda. Lift and browning.
1/4 teaspoon salt. Balance.

For the s’mores layer:

5 standard Hershey’s chocolate bars. Hershey’s is the s’mores default, though any chocolate bar works. Milk chocolate stays truer to a classic s’more. Dark chocolate cuts the sweetness if the marshmallow fluff feels like a lot.
1 1/2 cups marshmallow fluff. Also sold as marshmallow creme. This one is non negotiable.

The recipe card below has the full method. These are the steps and the technique notes that matter most. Prep takes about 15 minutes, baking takes 25 minutes, and the pan makes 16 bars.

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Preheat and line the pan. Heat the oven to 350F, line an 8×8 inch baking pan with parchment paper, and set it aside.
Cream the butter and sugars. Beat the butter with the granulated sugar and brown sugar until combined and light. Add the egg and the vanilla extract and mix again.
Add the dry ingredients. Add the flour, crushed graham crackers, salt, and baking soda. Mix just until the flour disappears. Overmixing is what makes bars tough, so stop as soon as the dough comes together.
Press and freeze the top layer. Press half the dough evenly into the prepared pan. The flat bottom of a measuring cup helps you get it level. Lift that dough layer out with the parchment and freeze it on a baking sheet while you build the bottom. This is the trick for a clean top layer that does not tear. Skip the freezer and the top dough will rip and the marshmallow will ooze.
Build the layers. Re line the pan with fresh parchment and press the second half of the dough into the bottom. Lay the Hershey’s bars across the dough, breaking pieces to fit any gaps. Spread the marshmallow fluff over the chocolate. Do not worry about reaching the edges, it spreads as it bakes. Flip the frozen dough layer on top, using the parchment to guide it, then peel the parchment off once it is in place.
Bake and cool completely. Bake for 25 minutes, until the top is golden. Then let the bars cool all the way before slicing. Slicing warm means the marshmallow has not set and the clean cross section is lost. Give them at least 2 hours at room temperature, or 45 minutes in the fridge if you want to speed things up.

The freezer step is the one shortcut you should not take. Cold dough holds its shape when you flip it onto the chocolate and fluff. Warm dough stretches, tears, and takes the marshmallow with it.
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What Makes These S’mores Bars Different from Traditional S’mores?

A traditional s’more is a roasted marshmallow and a square of chocolate sandwiched between two graham crackers, eaten outside, usually with marshmallow dripping down your wrist. It is messy in the best way, and it really only works when you have a fire.

These bars take those same elements and bake them into something sliceable. Graham shows up as cookie dough instead of a brittle cracker. The chocolate is a full bar in the middle, so it melts into a continuous layer instead of a hard square.

The marshmallow is fluff, which stays gooey even after a trip through the oven. Add a little structure from the cookie dough and the whole thing holds together.

That structure is the real difference. You can pack these bars in lunches, bring them to a picnic, or stack them on a platter without anything falling apart. You get s’mores flavor and s’mores nostalgia without the mess or the campfire.

Weigh the flour if you can. 1 1/2 cups of flour can range from about 180g to 220g depending on how you scoop. Too much flour is the number one reason cookie bars come out dry and cakey.
Do not skip freezing the top layer. Warm dough tears and stretches during transfer. The freezer is what gives you that neat stacked look.
Use full size Hershey’s bars, not chocolate chips. Chips stay in little pockets and will not give you a continuous melty chocolate layer.
Let the bars cool fully before slicing. This is the difference between great tasting but messy bars and great tasting bars that also look incredible.
Wipe the knife between cuts. Run a sharp knife under hot water, dry it, slice, wipe, and repeat. Clean edges every time.

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Variations and Substitutions

The base recipe is flexible, and most of these changes are easy to make without rethinking the whole method.

Double it for a crowd. Use a 9×13 pan and bake for 30 to 35 minutes, checking for a golden top.
Change the chocolate. Hershey’s milk chocolate is the classic move. Dark chocolate cuts the sweetness if the marshmallow fluff feels heavy. Both work.
Add chocolate chips to the dough. Extra chocolate in every bite, no other changes needed.
Try Hershey’s with almonds. A reader named Luz mentioned this in her review, and the crunch is a nice contrast to the gooey center.
Swap the graham crackers for crushed Biscoff cookies. The dough turns caramelized and cinnamon forward.
Make peanut butter s’mores bars. Swirl 2 tablespoons of creamy peanut butter into the marshmallow fluff before spreading it over the chocolate. If peanut butter and caramel are more your speed, these Peanut Butter Caramel Toffee Cookie Bars follow a similar layered logic.
Want a different bar entirely? These Chocolate Sugar Cookie Bars give you the same clean slice with a chocolate base.

These bars keep well, and honestly they taste even better on day two and day three.

Room temperature. Store in an airtight container for up to 3 days. The marshmallow layer stays gooey the whole time.
Refrigerator. Up to 1 week in an airtight container. The texture firms up cold, so let the bars sit at room temperature for 15 minutes before eating, or microwave a bar for 10 seconds to bring back that fresh baked gooey feel.
Freezer. Up to 2 months. Wrap individual bars in plastic wrap, place them in a freezer bag, and thaw at room temperature for a few hours or microwave for 20 seconds from frozen.
Make ahead. The dough can be made a day ahead and refrigerated. Let it sit at room temperature for 15 to 20 minutes before pressing it into the pan so it is workable.

Frequently Asked Questions

What are s’mores cookie bars made of?

They are layered bars built from graham cracker cookie dough on the top and bottom, with Hershey's chocolate bars and marshmallow fluff in the middle. The dough uses butter, brown sugar, granulated sugar, an egg, vanilla extract, all-purpose flour, finely crushed graham crackers, baking soda, and salt. One batch fills an 8×8 inch pan, bakes at 350°F for 25 minutes, and makes 16 servings.

Can I use mini marshmallows instead of marshmallow fluff?

Mini marshmallows are not the best swap because they melt and then set into a firmer, chewier layer, so you lose the gooey pull that defines these bars. The recipe calls for 1 1/2 cups of marshmallow fluff, also sold as marshmallow creme, which is the same product under a different name. Its corn syrup content keeps the center soft even after baking.

Why did my s’mores cookie bars sink in the middle?

A sunken center usually means the bars were underbaked or sliced before the marshmallow layer set. Cool them completely first, at least 2 hours at room temperature or about 45 minutes in the refrigerator, then slice. If the edges looked done but the middle had not set after cooling, bake 2 to 3 minutes longer next time and tent foil over the top if it browns too fast.

How should I store s’mores cookie bars and how long do they last?

Keep them in an airtight container at room temperature for up to 3 days, where the marshmallow layer stays gooey. For longer storage, refrigerate for up to 1 week or freeze individual wrapped bars for up to 2 months. Cold bars firm up, so let them sit at room temperature for 15 minutes or microwave briefly to bring back the fresh-baked texture.