S’mores Cookie Bars

April 29, 2026

The fastest way to get “campfire vibes” into a kitchen cookie bar is to build them right into the dough—and that’s exactly what these S’mores Cookie Bars do. You get a buttery, brown-sugar cookie base with graham cracker crumbs mixed in, plus pockets of chocolate chips and mini marshmallows that toast up on top.

They slice like bars (no scooping, no batches), but they eat like the center of a perfect cookie: soft and a little chewy at the edges, with gooey chocolate and those stretchy marshmallow threads when they’re still slightly warm. If you love bar recipes, you’ll probably also want to browse my cookies and bars collection—this one fits right in.

Why You’ll Love This Recipe

The graham cracker crumbs are mixed straight into the dough, so every bite has that toasty, “cracker” flavor—not just the topping.
Brown sugar + butter gives the bars a deeper caramel note, which plays really well with melty chocolate chips.
Mini marshmallows on top puff and lightly toast in the oven, making the surface look like a real s’mores situation.
It’s a single-pan bake: press, top, bake, cool, slice—much less fuss than portioning individual cookies.
These cut cleanly once cooled, but still stay soft in the center (especially where the marshmallows melt down into the dough).
Easy to “dress up” with extra chocolate chips and marshmallows right before baking for a bakery-style top.

The Story Behind This Recipe

I wanted a s’mores bar that tasted like more than just chocolate and marshmallow, so I started working graham cracker crumbs directly into the cookie dough—now the base itself brings that familiar flavor, and the whole pan smells like brown sugar and toasted graham while it bakes.

What It Tastes Like

These are sweet but not tooth-aching: the brown sugar reads warm and caramel-y, and the graham crumbs add a lightly nutty, toasty edge. The chocolate chips melt into pockets (especially in the middle), and the mini marshmallows puff and turn sticky, so you get a soft cookie-bar bite with gooey contrast and a slightly chewy edge.

Ingredients You’ll Need

Softened butter is key here—it creams smoothly with the brown and granulated sugars so the bars bake up tender, not dense. Graham cracker crumbs go right into the dough for that classic flavor throughout. Mini marshmallows work best on top (they toast and melt), and a little extra chocolate/marshmallow scattered over the surface makes the pan look loaded without changing the method. If you’re into other bar textures, my cake mix cookie bars are a fun shortcut-style option for comparison.

1 cup Unsalted butter, softened
1 cup Brown sugar, packed
1/2 cup Granulated sugar
2 Large eggs
1 teaspoon Vanilla extract
2 1/2 cups All-purpose flour
1 teaspoon Baking soda
1/2 teaspoon Salt
1 cup Graham cracker crumbs
1 cup Chocolate chips
1 cup Mini marshmallows
to taste Extra chocolate chips and marshmallows for topping

How to Make S’mores Cookie Bars

Prep your pan and oven. Heat the oven to 350°F. Grease a 9×13-inch baking pan so the bars lift out easily after cooling.
Cream the butter and sugars. In a large mixing bowl, beat the softened butter with the packed brown sugar and granulated sugar until the mixture looks lightened, fluffy, and creamy (you shouldn’t see streaks of butter).
Add eggs and vanilla. Beat in the eggs and vanilla extract until the batter looks smooth and glossy. (If it looks a little separated at first, keep mixing briefly—it should come together.)
Mix in the dry ingredients. Add the all-purpose flour, baking soda, salt, and graham cracker crumbs. Mix just until you don’t see dry flour; the dough will be thick and scoopable, like classic cookie dough.
Fold in the chocolate chips. Stir in the chocolate chips until evenly distributed—don’t overmix once the flour is in.
Press into the pan. Spread and press the dough into your prepared 9×13 pan in an even layer. A slightly damp hand can help press it flat without sticking.
Top like s’mores. Sprinkle the mini marshmallows over the top, then add extra chocolate chips and marshmallows to taste for a more “loaded” look.
Bake. Bake for 25–30 minutes, until the top looks light golden and the edges are set. The center should look set but still soft—it will firm up as it cools (overbaking is what makes these dry).
Cool completely, then slice. Let the bars cool in the pan before cutting. This is when the marshmallow and chocolate settle so you get cleaner squares. If you want inspiration for other clean-slicing layered bars, my cookies and cream magic bars are another favorite.

Tips for Best Results

Use truly softened butter. If it’s still cool and firm, it won’t cream well with the sugars and the bars can bake up heavier instead of tender.
Stop mixing once the flour disappears. Overmixing after adding flour can make the crumb tougher—mix just until combined, then fold in chips.
Aim for an even dough layer. If the corners are thinner, they’ll bake faster and get crunchier than the center.
Watch the color, not just the clock. Pull them when the edges look set and the top is just turning golden; the middle will continue to set as it cools.
Cool fully for neat slices. Warm bars taste great but cut messy because the marshmallows and chocolate are still molten. For the cleanest cuts, cool completely and use a sharp knife.

Variations and Substitutions

More topping, same base: Go heavier on the extra chocolate chips and marshmallows on top for a more dramatic finish (especially nice for parties).
Make them extra gooey: Bake toward the lower end of the time range and let them cool until just warm—this keeps the center softer.
Different bar vibe: If you prefer a no-oven treat with a similar “slice into squares” payoff, try my no-bake cookie dough bars on another day.

How to Serve It

These are happiest served slightly warm (not hot), when the chocolate is still a little melty and the marshmallow stretches without falling apart. For clean, sharable squares, cool completely and slice, then stack on a platter—those toasted marshmallows on top make them look finished without any extra work. If you’re packing them up, place parchment between layers so the marshmallow tops don’t stick.

How to Store It

Store the cooled bars in an airtight container at room temperature for a few days. Because the marshmallow topping can get sticky, it helps to separate layers with parchment or wax paper. If you’re making them ahead for an event, bake and cool the day before, then slice closer to serving for the neatest edges.

Final Thoughts

If you want the flavor of s’mores without the mess of a fire pit, this pan delivers: graham cracker cookie base, melted chocolate pockets, and a toasted marshmallow top that looks as good as it tastes. Bake them until just set, let them cool, and you’ll have bars that disappear fast.

Conclusion

If you’re curious how other bakers build their s’mores bars, you can compare approaches with Sally’s version of S’mores Cookie Bars (Recipe + Video), this homey take on S’mores Cookie Bars, or the straightforward S’mores Cookie Bar Recipe—then come back and make the one that best matches your ideal marshmallow-to-chocolate ratio.