Gooey S’mores Cookie Bars Recipe | Chewy Homemade Dessert Bars

ByAlex King March 19, 2026

Craving campfire s’mores without the smoke and sticky fingers? These gooey s’mores cookie bars bake all the best parts—graham, marshmallow, and chocolate—into thick, chewy dessert squares you can slice and share. They’re rich, nostalgic, and wildly satisfying.

I make these bars when I want maximum payoff with minimum fuss. The dough comes together fast, the layers melt into a glorious goo, and the whole pan disappears in record time. If you love a chewy cookie and a melty s’more, you just found your new go-to dessert.

Why These S’mores Cookie Bars Turn Out So Good

You get the classic flavors you love with a texture that beats a campfire sandwich any day. Here’s why they deliver every time:

Chewy meets gooey: A soft brown-sugar cookie base hugs melty marshmallows and pools of chocolate.
Graham in every bite: Crushed graham crackers mix right into the dough for flavor and crunch.
No special gear: A mixing bowl, a pan, and a spatula get it done.
Make-ahead friendly: The dough chills well and the bars keep beautifully.
Perfect for sharing: Slice into clean squares—no campfire chaos.

Ingredients

For the cookie dough base

1 1/2 cups (190g) all-purpose flour
3/4 cup (75g) finely crushed graham crackers (about 6 full sheets)
1/2 teaspoon baking soda
1/2 teaspoon fine sea salt
1/2 cup (113g) unsalted butter, melted and slightly cooled
3/4 cup (150g) packed light brown sugar
1/4 cup (50g) granulated sugar
1 large egg + 1 egg yolk (room temp for best texture)
2 teaspoons pure vanilla extract

For the s’mores layers

1 1/2 cups (255g) semisweet or milk chocolate chips or chunks
2 cups mini marshmallows (or cut full-size marshmallows into pieces)
2–3 graham cracker sheets, broken into small pieces (optional for the top)

Pan and finish

8-inch or 9-inch square baking pan (line with parchment for easy lifting)
Flaky sea salt for finishing (optional but excellent)

How to Make Chewy S’mores Cookie Bars

1) Prep the pan and oven

Heat oven to 350°F (175°C).
Line your 8- or 9-inch square pan with parchment, leaving an overhang for lifting.

2) Mix the dry ingredients

In a bowl, whisk flour, crushed graham crackers, baking soda, and salt until blended.

3) Whisk the wet ingredients

In a larger bowl, whisk melted butter, brown sugar, and granulated sugar until glossy and smooth.
Whisk in the egg, egg yolk, and vanilla until the mixture looks thick and uniform.

4) Bring the dough together

Add dry ingredients to wet and stir with a spatula until no dry streaks remain. The dough will feel soft and sticky—perfect.

5) Layer the bars

Press about two-thirds of the dough into the pan in an even layer.
Scatter chocolate chips evenly over the dough.
Top with an even layer of mini marshmallows.
Dot the remaining dough over the top in flattened pieces, leaving some gaps so the marshmallow can bubble through.
Sprinkle with graham pieces and a pinch of flaky salt if using.

6) Bake and cool

Bake for 22–28 minutes, until the edges look set and deep golden and the top shows toasty marshmallow spots.
Cool in the pan on a rack for at least 45–60 minutes so the bars set. Lift out with parchment and slice.

Pro tips for great texture

Don’t overbake: Pull them while the center still looks soft; carryover heat finishes the job.
Use mixed chocolate: Combine milk and semisweet for flavor depth and extra goo.
Chill for ultra-neat slices: A quick 20–30 minutes in the fridge firms the marshmallow for clean cuts.

How to Store S’mores Cookie Bars

Room temperature: Store slices in an airtight container for 2–3 days. Layer with parchment to prevent sticking.
Refrigerate: Keep up to 5 days for firmer bars. Let them sit 10 minutes before serving to soften.
Freeze: Wrap individual bars tightly and freeze up to 2 months. Thaw at room temp or warm gently.
Reheat: Microwave a bar for 8–12 seconds for that fresh-from-the-oven goo.

Why You’ll Love Making These Bars

All-in-one dessert: Cookies, chocolate, and marshmallow in one easy pan.
Kid- and crowd-approved: The nostalgic flavor hits every time.
Scales easily: Double the recipe in a 9×13 pan and add 5–10 minutes to bake time.
Low mess, high reward: No skewers, no campfire, no crumbs everywhere.

Mistakes to Avoid

Overmixing the dough: Stir just until combined to keep the crumb tender and chewy.
Skipping parchment: You’ll fight to get them out clean—parchment saves the day.
Overbaking: Marshmallows darken fast; watch at the 20-minute mark.
Cutting too soon: Warm marshmallow sticks; give the bars time to set for clean slices.
Using only one chocolate type: Mix milk and dark for balance and better melt.

Tasty Variations to Try

Peanut butter swirl: Warm 1/4 cup creamy peanut butter and drizzle over the chocolate layer.
Cookies and cream: Fold 1/2 cup crushed chocolate sandwich cookies into the dough.
Salted caramel: Dot 1/3 cup soft caramel bits between chocolate and marshmallow; finish with flaky salt.
Espresso chocolate: Add 1 teaspoon instant espresso powder to the dough for mocha vibes.
Nutty crunch: Sprinkle 1/2 cup chopped toasted pecans or almonds over the chocolate.
Gluten-free swap: Use a 1:1 gluten-free flour blend and gluten-free graham crackers.

FAQ

Can I use marshmallow fluff instead of mini marshmallows?

Yes. Spread 1 to 1 1/2 cups marshmallow creme over the chocolate. Chill the pan 10 minutes before topping with the remaining dough to make spreading easier.

Can I make these ahead?

Absolutely. Bake, cool, and slice up to 24 hours ahead. Store airtight at room temp. Warm briefly before serving for extra goo.

What size pan works best?

An 8-inch square pan makes thicker, gooier bars. A 9-inch pan yields slightly thinner bars and bakes a few minutes faster.

How do I prevent marshmallows from melting away?

Use mini marshmallows and avoid placing them directly against hot pan edges. Bake until lightly toasty, not deeply browned.

Can I reduce the sugar?

You can cut the granulated sugar by 2–3 tablespoons without hurting texture. Keep the brown sugar for chewiness.

How do I double the recipe?

Use a 9×13-inch pan, double all ingredients, and bake for 28–34 minutes, watching for golden edges and set center.

Conclusion

These gooey s’mores cookie bars pack everything you love about the campfire classic into thick, chewy squares you can bake anytime. Keep the ingredients on hand and you can whip up a pan whenever a craving hits. Slice, share, and enjoy the melt-with-every-bite magic—no campfire required.