Name: S'mores Cookie Bars
Prep time: 15 min
Cook time: 25 min
Total time: 40 min
Ingredients: 115g (1/2 cup) unsalted butter, softened; 100g (1/2 cup) packed light brown sugar; 100g (1/2 cup) granulated sugar; 1 large egg; 1 tsp vanilla extract; 150g (1 1/4 cups) all-purpose flour; 120g (1 cup) fine graham cracker crumbs; 1/2 tsp baking soda and 1/2 tsp salt; 250g (1 1/2 cups) semi-sweet chocolate chips; 75g (1 1/2 cups) mini marshmallows

The other day, Noah and Lily were begging Jake to build a campfire in the backyard because they were craving s’mores. Since it was pouring rain here in Austin, a fire was completely out of the question. I promised them we could make something even better inside, and these S’mores Cookie Bars absolutely delivered. We built a living room fort instead, and they devoured every single gooey, chocolate-filled bite without a single complaint.

These S’mores Cookie Bars bring all the classic campfire flavors right into your kitchen with a fraction of the mess. We are combining a soft graham cracker cookie dough with a thick layer of melting chocolate and toasted marshmallows. This recipe bakes up in under thirty minutes, creating a golden, buttery crust with the most incredible gooey center. If you want a fun, family-friendly dessert that requires zero outdoor equipment, this is exactly what you need.

Why You'll Love This Recipe

No Campfire Needed: You get all the toasted marshmallow and melting chocolate flavor without having to step outside or smell like smoke.
Incredible Gooey Center: The middle stays perfectly soft, giving you that authentic messy s'mores experience in a neat little bar.
Simple One-Pan Prep: Everything bakes together in an eight-inch square pan, making cleanup an absolute breeze.
Kid-Approved Magic: The combination of sweet graham cracker dough and fluffy marshmallows is guaranteed to make your little ones smile.
Travels Beautifully: Unlike traditional s'mores, these bars hold their shape, making them perfect for lunchboxes or indoor picnics.

Ingredients You'll Need

This recipe takes all the classic elements of a s’more and binds them together with basic baking staples you probably already have in your pantry.

115g (1/2 cup) unsalted butter, softened – the base of our rich cookie dough.
100g (1/2 cup) packed light brown sugar – adds moisture and a slight caramel flavor.
100g (1/2 cup) granulated sugar – gives the cookie bars a perfectly crisp edge.
1 large egg – binds the dough together so it holds its shape.
1 tsp vanilla extract – adds a comforting, aromatic background note.
150g (1 1/4 cups) all-purpose flour – gives the bars structure.
120g (1 cup) graham cracker crumbs – this replaces some of the flour to give the dough that authentic campfire flavor.
1/2 tsp baking soda and 1/2 tsp salt – essential for lift and flavor balance.
250g (1 1/2 cups) semi-sweet chocolate chips – you can also chop up classic chocolate bars if you prefer.
75g (1 1/2 cups) mini marshmallows – these melt perfectly and create that signature gooey layer.

To get the best graham cracker flavor in the dough, I highly recommend using a food processor to crush your graham crackers into very fine, sandy crumbs. If the pieces are too large, the cookie dough will not hold together properly and your bars will crumble when you try to slice them.

When it comes to the chocolate layer, you have complete freedom. Semi-sweet chocolate chips hold their shape beautifully in the oven, but if you want pools of melted chocolate, chop up a standard milk chocolate bar instead. The combination of milk chocolate and sweet marshmallows creates a truly authentic campfire taste.

Note: Make sure your butter is softened to room temperature, not melted. Melted butter will cause the graham cracker dough to spread too much, leaving you with a flat, greasy base instead of a thick and chewy cookie bar.

How to Make S'mores Cookie Bars

Layering these bars is incredibly fun, and it is a great step to let the kids help out with in the kitchen.

Step 1: Prepare your baking pan.

Preheat your oven to 175°C (350°F). Line an 8×8 inch square baking pan with parchment paper, making sure to leave a slight overhang on two sides. This overhang acts like a sling, making it so much easier to lift the sticky bars out of the pan later.

Step 2: Cream the butter and sugars.

In a large mixing bowl, beat the softened butter, brown sugar, and granulated sugar together until light and fluffy. Add the large egg and vanilla extract, mixing until everything is completely smooth and creamy.

Step 3: Add the dry ingredients.

Pour the all-purpose flour, fine graham cracker crumbs, baking soda, and salt into the wet mixture. Stir gently with a wooden spoon until a thick, crumbly dough forms.

Lora’s Tip: Do not overmix the dough once the flour is added. You want the bars to stay tender and soft, not dense.

Step 4: Build the base layer.

Press slightly more than half of the graham cookie dough into an even layer at the bottom of your prepared pan. Scatter the chocolate chips and mini marshmallows in a thick, even layer directly over the dough.

Step 5: Add the topping.

Flatten small pieces of the remaining cookie dough in the palms of your hands and place them gently over the marshmallow layer. It is perfectly fine if some marshmallows peek through the gaps in the top.

Lora’s Tip: Leaving a few gaps in the top dough layer actually allows the marshmallows to toast and turn golden brown while baking.

Step 6: Bake and cool.

Bake for 20 to 25 minutes until the top is golden brown and the marshmallows look puffed and toasted. Let the pan cool completely on a wire rack before using the parchment overhang to lift and slice.

Lora's Kitchen Tips

Crush crumbs finely. The finer your graham cracker crumbs, the smoother and more cohesive your cookie dough will be.
Spray your measuring cup. If your marshmallows are sticking, lightly coat your measuring cup with nonstick spray before scooping them.
Let them cool fully. Cutting into hot s'mores bars will result in a completely melted, gooey mess. Wait at least two hours before slicing.
Use a warm knife. Run a sharp chef's knife under hot water and wipe it dry between slices to cut cleanly through the sticky marshmallows.
Press the base firmly. Use the bottom of a glass to firmly pack the bottom layer of dough so it can support the heavy chocolate center.

Variations and Substitutions

These bars are incredibly easy to customize depending on what you happen to have hiding in your pantry.

The Peanut Butter Twist: Swap half of the semi-sweet chocolate chips for peanut butter chips to create an incredible chocolate-peanut butter flavor profile.

The Dark Chocolate Option: If you find traditional s’mores a bit too sweet, use dark chocolate chunks and reduce the granulated sugar by a few tablespoons to balance the flavors.

The Salty Crunch Addition: Sprinkle a tiny pinch of flaky sea salt or a handful of crushed pretzels over the marshmallow layer before baking for an amazing sweet and salty contrast.

The Gluten-Free Swap: You can replace the all-purpose flour with a 1-to-1 gluten-free baking blend, and make sure to use certified gluten-free graham crackers for the crumbs.

What to Serve with S'mores Cookie Bars

These bars are rich, chewy, and loaded with chocolate, making them the ultimate standalone treat for movie nights or afternoon snacks.

I almost always serve these with a tall, ice-cold glass of milk. The milk cuts through the dense, gooey sweetness of the toasted marshmallows perfectly. If you are having guests over, serving these slightly warm with a scoop of vanilla bean ice cream is an absolute game changer. Hawaiian Carrot Pineapple Cake

If you are packing these for a lunchbox or an indoor picnic, they pair wonderfully with fresh, crisp fruit like sliced strawberries or Heaven on Earth Cake.

Storage, Freezing, and Reheating

Storage: Keep the sliced bars in an airtight container at room temperature for up to 4 days.
Freezing: Wrap individual bars tightly in plastic wrap and then foil. Freeze for up to 3 months for a quick sweet treat.
Layering tip: If stacking the bars in a container, place a sheet of parchment paper between the layers so they do not stick.
Microwave magic: Pop a room-temperature bar into the microwave for exactly 10 seconds to make the center perfectly gooey again.
Thawing method: Let frozen bars sit at room temperature for an hour before eating so the cookie base softens completely.

Frequently Asked Questions

Here are the questions I get asked most often about these easy s’mores cookie bars:

Can I use marshmallow fluff instead of mini marshmallows?

I do not recommend using marshmallow fluff for this recipe. Fluff tends to melt directly into the cookie dough while baking, leaving you without that distinct, gooey marshmallow layer.

Why did my bars turn out hard and crumbly?

Hard cookie bars usually happen when the flour is over-measured or the dough is overmixed. Always spoon your flour into the measuring cup instead of scooping it directly from the bag.

Can I double this recipe for a party?

Absolutely! You can double all the ingredients and bake the bars in a 9×13 inch rectangular baking dish. You may need to add 5 to 8 extra minutes to the baking time.

Do I have to use parchment paper?

Parchment paper is highly recommended. The melted marshmallows will stick stubbornly to the sides of a bare baking pan, making it nearly impossible to remove the bars in one piece.

Can I use large marshmallows cut into pieces?

Yes, if you only have large campfire marshmallows, simply use kitchen shears to snip them into quarters. Toss the sticky pieces in a tiny pinch of powdered sugar to keep them from clumping.

These S’mores Cookie Bars are proof that you do not need a campfire to enjoy the best flavors of summer. The buttery graham cracker dough, the pools of melted chocolate, and the toasted marshmallow topping come together to create a dessert that your entire family will obsess over. I hope you bake a batch of these for your next movie night, and please let me know how quickly they disappear from your kitchen.

With love and extra chocolate,
Lora x