Decadent S'mores Cookie Bars You'll Crave Forever

Name: S'mores Cookie Bars
Prep time: 15 min
Cook time: 25 min
Total time: 40 min
Cuisine: American
Ingredients: 1 1/2 cups graham cracker crumbs; 1/2 cup unsalted butter, melted; 1/4 cup granulated sugar; 1 cup all-purpose flour; 1/2 tsp baking powder; 1/4 tsp salt; 1/2 cup unsalted butter, softened; 3/4 cup brown sugar; 1 large egg; 1 tsp vanilla extract; 1 cup chocolate chunks; 1 1/2 cups mini marshmallows

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You know that magical moment when the campfire crackles, marshmallows turn golden, and chocolate melts into graham crackers? That’s exactly what these s’mores cookie bars capture—without the campfire smoke in your hair! I first fell in love with this recipe during a summer potluck when my cousin brought a pan, and let me tell you, it vanished faster than fireflies at dusk. Now I make them for every gathering—they’ve got that irresistible combo of gooey marshmallow swirls, melty chocolate chunks, and a buttery graham cracker crust that holds together beautifully. No skewers required, just pure nostalgia in every chewy, crunchy bite.

Table of Contents

Why You'll Love These S'mores Cookie Bars
Ingredients for S'mores Cookie Bars
How to Make S'mores Cookie Bars
- Tips for Perfect S'mores Cookie Bars
Variations for S'mores Cookie Bars
Serving and Storing S'mores Cookie Bars
Nutritional Information for S'mores Cookie Bars
Frequently Asked Questions
Share Your S'mores Cookie Bars

These bars are my go-to dessert for a reason. Here’s why they’ll become your new favorite:

That irresistible texture: Gooey marshmallow swirls, melty chocolate chunks, and a crisp graham cracker crust create the perfect bite
Foolproof to make: No campfire skills required – just mix, layer, and bake in under 30 minutes
Party perfection: One pan makes 16 neat squares that disappear fast at potlucks (trust me, I’ve seen it happen!)
Tastes like childhood: All the nostalgic flavors of summer nights, packed into easy-to-eat bars
Slices like a dream: Unlike messy s’mores, these hold their shape beautifully when cut

You’ll love how simple these s’mores cookie bars come together with basic ingredients! I’ve grouped everything below so you can check your pantry before baking. And trust me—using real butter and fresh graham crackers makes all the difference in flavor.

For the Graham Cracker Crust

1 1/2 cups graham cracker crumbs (about 10 full sheets crushed—I like Honey Maid)
1/2 cup unsalted butter, melted (go for the good stuff—it adds rich flavor)
1/4 cup granulated sugar (helps the crust caramelize slightly)

1 cup all-purpose flour (spoon and level it—don’t scoop directly from the bag!)
1/2 tsp baking powder (gives just the right lift without puffing too much)
1/4 tsp salt (balances all that sweetness perfectly)
1/2 cup unsalted butter, softened (room temp is key for creaming properly)
3/4 cup brown sugar (dark brown sugar adds amazing depth)
1 large egg (always crack into a separate bowl first—shells happen!)
1 tsp vanilla extract (pure vanilla gives better flavor than imitation)
1 cup chocolate chunks (I splurge on Guittard—those big melty pockets are worth it)

For the Topping

1 1/2 cups mini marshmallows (the small size melts into perfect gooey swirls—don’t substitute large ones!)

See? Nothing too fancy—just quality ingredients that transform into pure magic. Pro tip: measure everything before you start mixing. It makes the process so much smoother (and prevents those “oh no, I’m out of eggs!” moments).

Alright, let’s make some magic happen! These s’mores cookie bars are simpler than you think – I’ll walk you through each step like we’re baking side by side in my kitchen. Just follow these easy instructions, and you’ll be sharing these gooey delights in no time.

Preheat your oven to 350°F. Grab a 9×9-inch baking pan—this size gives you the perfect bar thickness. Here’s my secret weapon: line it with parchment paper, leaving some overhang on the sides. You’ll thank me later when your bars lift out perfectly!
Make the crust: In a bowl, mix together your graham cracker crumbs, melted butter, and sugar until it resembles wet sand. Now press it firmly into your prepared pan—I use the bottom of a measuring cup to get it nice and even. This crust is your foundation, so pack it down tight! (Pro tip: If you’re feeling fancy, you can bake this crust alone for 5 minutes first for extra crunch.)
Whisk dry ingredients—that’s your flour, baking powder, and salt—in a separate bowl. I always sift them together to prevent lumps. Set this aside while you work on the cookie dough.
Cream the butter and brown sugar until light and fluffy—about 2-3 minutes with a mixer. Add the egg and vanilla, mixing until just combined. Now slowly add your dry ingredients. The dough will be thick and magical already!
Fold in chocolate chunks gently—don’t overmix! Spread this dough over your graham cracker crust. I find wetting my fingertips helps smooth it out without sticking too much.
Bake for 20 minutes—the top should look set but still soft. Now comes the fun part! Sprinkle those mini marshmallows across the top. Return to the oven for just 5 more minutes—watch closely as they puff up and turn golden. A quick broil (30 seconds!) gives them that perfect campfire toast if you’re feeling fancy.
Cool completely—I know, the hardest part! But trust me, rushing this means messy slices. Let them sit at room temperature for at least an hour. The marshmallows will firm up just enough for perfect cutting.
Slice with a hot knife—dip your knife in hot water and wipe dry between cuts for those picture-perfect clean edges everyone will rave about.

A close-up of a decadent s'mores cookie bar slice on a gray plate, featuring a graham cracker crust, chocolate ganache, and toasted marshmallows.

See? Easy as (cookie bar) pie! The hardest part is waiting for them to cool before diving in. If you love classic chocolate chip cookies, you’ll adore these bars—they’re like my thick chewy chocolate chip cookies got a s’mores makeover!

Here are my foolproof tricks for bar perfection every time:

Hot knife magic: Seriously, dipping your knife in hot water makes slicing through sticky marshmallows a breeze!
Patience pays: Let them cool completely—at least 1 hour—or you’ll have a delicious but messy situation.
Crust matters: Press that graham cracker layer firmly and evenly—it prevents crumbling when you slice.

Oh, the fun part! These bars are like a blank canvas for your wildest s’mores dreams. Here are my favorite ways to mix things up:

Peanut butter paradise: Swirl in 1/4 cup melted peanut butter before adding marshmallows – it tastes like a Reese’s cup had a baby with a s’more!
Salty-sweet crunch: Sprinkle crushed pretzels over the marshmallows before baking. That salty punch cuts through the sweetness perfectly.
Caramel lovers: Drizzle store-bought or homemade caramel sauce at the end. Pro tip: Warm it slightly so it flows beautifully.
White chocolate twist: Replace half the chocolate chunks with white chocolate chips for a creamy contrast.
Diet-friendly swaps: Use gluten-free graham crackers or keto marshmallows if needed – they work surprisingly well!

A stack of three decadent s'mores cookie bars, topped with toasted marshmallows and melted chocolate.

The best part? You can combine these ideas too (peanut butter AND pretzels? Yes please!). Just keep the total add-ins to about 1 1/2 cups so the bars hold together.

Now comes my favorite part – eating these beauties! But first, let me share all my secrets for serving them just right and keeping them fresh (if they last that long in your house!).

Serving: These bars are heaven at room temperature when the chocolate is slightly soft but the marshmallow has that perfect chewy pull. If you prefer warm, gooey goodness, pop a square in the microwave for 10 seconds – just enough to make the chocolate melty and the marshmallow stretchy without turning into a sticky mess. I love serving them with cold milk or coffee – that contrast of temperatures is magic!

Storing: Here’s how I keep mine tasting fresh (though they rarely last more than a day in my house):

Let them cool completely first (I know, the hardest part!)
Layer them in an airtight container with parchment between layers if stacking
Room temperature for 3 days max (the marshmallows start weeping after that)
Pop a slice of bread in the container – it keeps the bars from drying out!

A close-up of a decadent s'mores cookie bar topped with toasted marshmallows and drizzled with chocolate sauce.

Make-Ahead Magic: These bars are perfect for planning ahead! You’ve got options:

Freeze unbaked dough: Press the graham cracker crust in the pan, then spread the cookie dough over it. Wrap the whole pan well in plastic and freeze for up to 2 months. When ready, thaw slightly, top with marshmallows, and bake as directed (add a couple extra minutes if baking from frozen).
Freeze baked bars: Let them cool completely, then freeze in individual portions wrapped in parchment. They thaw at room temp in about 30 minutes – or microwave frozen for 15 seconds!

Pro tip: If your marshmallows get a little too toasty in storage (they sometimes do), just scrape off the top layer with a butter knife – the gooey goodness underneath is still perfect!

Listen, we both know these indulgent bars aren’t exactly a salad—they’re meant to be a treat! While I don’t count calories when enjoying my grandma’s recipes, I know some of you like to keep track. Just remember, these numbers are estimates only based on average ingredients. Your exact values will change depending on which chocolate chunks you splurge on or whether you use salted vs. unsalted butter.

The beauty of homemade desserts is that you control the ingredients—want to lighten it up? Try reduced-fat graham crackers or dark chocolate with less sugar. Making substitutions? The nutrition will vary. That’s the joy (and sometimes the frustration!) of baking from scratch.

My philosophy? Life’s too short not to enjoy a gooey, chocolatey bar sometimes—especially when they’re made with love and shared with people you care about. But if you’re tracking for specific dietary needs, always calculate based on your exact ingredients. Now go enjoy that perfectly toasted marshmallow top!

Frequently Asked Questions

I get so many questions about these s’mores cookie bars—let me answer the ones that pop up most often! Trust me, I’ve made every mistake so you don’t have to. Here’s everything you need to know:

Can I use regular marshmallows instead of mini ones?

Technically yes, but mini marshmallows work best for this recipe! The small size melts into perfect gooey pockets rather than creating one thick layer that could pull off when slicing. If you only have large marshmallows, try cutting them into quarters with kitchen shears (lightly oiled scissors help prevent sticking).

How do I prevent burnt marshmallows on top?

Watch them like a hawk during those last 5 minutes! My trick: add the marshmallows after the cookie layer bakes, then just give them enough time to puff and lightly brown—no more than 5 minutes. If your oven runs hot, try 4 minutes. For extra insurance, you can tent the pan with foil during this last bake.

Can I double this recipe for a crowd?

Absolutely! Just use a 9×13-inch pan instead (double all ingredients). Bake the base layer for 22-25 minutes before adding marshmallows. These make perfect potluck desserts—I always double the batch for game nights and school events. Pro tip: the bars will be thicker, so extend cooling time to 2 hours before cutting.

Why does my graham cracker crust crumble when slicing?

Two likely culprits: Not enough butter in the crust mixture (measure carefully!) or not pressing it firmly enough. Really pack it down—I use the bottom of a glass to create an even, compact layer. Also, make sure you let the bars cool completely; cutting warm makes everything more likely to crumble.

Can I make these ahead and freeze them?

You sure can—they freeze beautifully! Here’s how: Cool completely, then wrap individual bars in parchment paper before freezing in an airtight container. Thaw at room temp for 30 minutes when ready to eat. For best texture, I actually prefer freezing the unbaked dough—just assemble as directed (minus marshmallows) in a freezer-safe pan, wrap well, and bake straight from frozen (add 5 extra minutes). Add marshmallows at the end as usual!

I’d love to see your creations—did you add a fun twist or nail that perfect marshmallow toast? Snap a pic and share it with me on Pinterest (I’m @KitchenUser) or leave a rating below! Nothing makes me happier than seeing these gooey bars bring smiles to your kitchen too.

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