S’mores Cookie Bars

May 10, 2026

Brown sugar and butter do something magical in the oven—especially when you fold in graham cracker crumbs, puddles of chocolate chips, and a scatter of mini marshmallows. These S’mores Cookie Bars bake up thick and golden, with crisp edges, a chewy center, and those toasty little marshmallow pockets that taste like the best part of a campfire treat.

If you love a cookie-bar situation that slices cleanly but still eats soft and gooey, this one’s for you. It’s a straightforward one-bowl-style dough (cream, mix, fold, bake), and the graham crumbs make the whole pan smell like a warm, buttery cracker crust. If you’re in a cookie mood, you might also like my chocolate chip cookie cake—same cozy vibe, different payoff.

Why You’ll Love This Recipe

The graham cracker crumbs bake right into the dough, giving you that unmistakable s’mores flavor without extra layers.
You get contrast in every bite: crisp, caramelized edges; a chewy, buttery middle; and little sticky hits of marshmallow.
Brown sugar + granulated sugar balance each other—deep molasses warmth with a clean sweetness that keeps the bars from tasting flat.
The dough is sturdy enough to hold marshmallows and chips without turning into a gooey mess when you slice.
The “to taste” topping lets you dial up the drama—a few extra chips and marshmallows on top make the pan look bakery-worthy.

The Story Behind This Recipe

I wanted a s’mores-inspired bar that didn’t require building layers or juggling candy bars—just one dependable cookie base with graham crumbs mixed right in. It’s the kind of recipe I reach for when I’m craving that toasted marshmallow/chocolate combo but still want something that feels like a real cookie at heart (if you’re a stuffed-cookie person too, my cheesecake-stuffed chocolate chip cookies live in the same “one more bite” category).

What It Tastes Like

These bars taste like a buttery chocolate chip cookie that decided to wear a graham cracker sweater. The vanilla and brown sugar come through first—warm, caramel-y, and rich—then you hit melty chocolate and little pops of sweet marshmallow that toast on top. Texture-wise, expect chewy centers with occasional gooey spots (where marshmallows melt), plus golden edges that snap just a bit when you bite in.

Ingredients You’ll Need

A few ingredients do the heavy lifting here: softened butter helps you cream up a light, fluffy base so the bars don’t bake up dense; graham cracker crumbs bring that honeyed, toasty flavor; and mini marshmallows distribute more evenly than big ones, so you get gooey pockets without massive sinkholes. Stick with unsalted butter so the salt level stays in your control—especially important with sweet add-ins like chocolate chips.

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 (175°C). Grease a 9×13-inch baking pan so the bars release easily after baking.
Cream the butter and sugars. In a large bowl, beat the softened butter with the packed brown sugar and granulated sugar until the mixture looks lighter in color and fluffy, not greasy or separated.
Add eggs and vanilla. Beat in the eggs, then the vanilla extract, mixing until the batter looks smooth and glossy.
Mix in the dry ingredients. Add the flour, baking soda, salt, and graham cracker crumbs. Mix just until you no longer see streaks of flour; the dough will be thick and scoopable.
Fold in the fun stuff. Stir in the chocolate chips and mini marshmallows until they’re evenly distributed. (Try not to overmix—too much stirring can make the bars bake up tougher.)
Press into the pan. Spread the dough into the prepared pan and press it into an even layer—this helps the bars bake uniformly from edge to center.
Top it off. Sprinkle extra chocolate chips and marshmallows over the top “to taste.” (A light, even scatter gives you picture-perfect slices; a heavier hand gives you extra gooey, toasty patches.)
Bake. Bake for 25–30 minutes, until the top is golden brown and the center looks set (it shouldn’t jiggle like raw dough). Marshmallows on top will look toasted in spots.
Cool completely, then slice. Let the bars cool in the pan before cutting—this is the difference between clean squares and a molten scoop. For more cookie bar inspiration later, my easy blueberry cheesecake swirl cookie is another great “slice-and-serve” bake.

Tips for Best Results

Use truly softened butter. It should indent easily when you press it, but not look shiny or melted—this helps the sugars cream properly and keeps the texture chewy instead of greasy.
Don’t overbake. Pull the pan when the center looks set and the edges are golden. The bars will finish setting as they cool, and overbaking can make the graham-crumb cookie base dry.
Save some marshmallows for the top. Marshmallows mixed into the dough give gooey pockets; marshmallows on top give that classic toasted look (and a slightly crisp, sticky surface).
Cool all the way before slicing. Warm marshmallow can drag your knife and tear the bars. If you’re impatient, give them extra time—then slice with a steady downward cut.
Aim for an even thickness. Pressing the dough flat (especially into the corners) prevents the center from staying underbaked while the edges get too dark.

Variations and Substitutions

More graham flavor: Add a slightly heavier sprinkle of graham cracker crumbs on top before baking for a toastier aroma and a speckled finish.
Chocolate level: Use your “to taste” topping to increase the chocolate presence—extra chips on top melt into glossy little pools.
Marshmallow level: Keep the mixed-in amount the same, but add more to the top if you want more toasted pockets (just know the top will be stickier when sliced).

How to Serve It

Slice into squares once fully cool, then serve as-is for the cleanest edges and the chewiest bite. If you like them extra gooey, warm a bar briefly so the chocolate softens and the marshmallows get a little stretchy. I love these with cold milk, or alongside a simple cup of coffee for a sweet/salty contrast. If you’re building a cookie platter, tuck these next to something no-bake like my healthy chocolate peanut butter no-bake oatmeal cookies for variety in texture.

How to Store It

Store the bars in an airtight container at room temperature so they stay chewy. If your kitchen runs warm, you can refrigerate them, but the texture will firm up (still tasty—just less gooey). For longer storage, freeze sliced bars in a freezer-safe container; thaw at room temperature before serving. If you’ve topped with a lot of marshmallows, know the tops stay a bit sticky—separating layers with parchment helps.

Final Thoughts

If you’re craving s’mores flavor without the campfire logistics, these cookie bars hit the mark: graham-sweet, chocolate-studded, and dotted with toasted marshmallow in every slice. Keep a few squares tucked away for the next time you want a low-effort, high-reward bake.

Conclusion

If you’d like to compare approaches (and see how other bakers handle the marshmallow-to-chocolate balance), take a look at Sally’s S’mores Cookie Bars (Recipe + Video), this cozy, straightforward S’mores Cookie Bars version, or the classic S’mores Cookie Bar Recipe for more inspiration—then come back and make this batch your own. And for site details you might be looking for, my cookie policy is always available.