If you love the classic combination of chocolate, graham crackers, and toasted marshmallows, these S’mores Cookie Bars are the perfect homemade dessert. They combine everything you love about traditional campfire s’mores with the soft, chewy texture of chocolate chip cookies.
Each bar features a buttery brown sugar cookie base packed with chocolate chips, crunchy graham crackers, gooey marshmallows, and pieces of chocolate. As the bars bake, the chocolate melts into the cookie dough while the marshmallows become soft and lightly toasted, creating a delicious dessert with plenty of texture in every bite.
The best part? You can enjoy all the nostalgic flavor of s’mores without building a campfire. These cookie bars are baked in one pan, making them ideal for parties, summer gatherings, family movie nights, potlucks, and bake sales.
Whether you serve them slightly warm with melted chocolate or let them cool for neat, chewy squares, these homemade S’mores Cookie Bars are guaranteed to satisfy your sweet tooth.
Why You’ll Love These S’mores Cookie Bars
- Soft and chewy texture: Melted butter and brown sugar help create a rich cookie base.
- Classic s’mores flavor: Chocolate, marshmallows, and graham crackers come together in every bite.
- Loaded with chocolate: Chocolate chips and pieces of a chocolate bar add plenty of sweetness.
- Easy to prepare: The cookie dough comes together with simple baking ingredients.
- Perfect for sharing: Cut the finished dessert into squares for parties, picnics, or family gatherings.
- No campfire required: Enjoy the flavor of traditional s’mores from your own kitchen.
Ingredients for S’mores Cookie Bars
These ingredients make a batch of cookie bars that can be cut into approximately 12–16 squares, depending on how large you want each serving.
For the Cookie Dough
- 2 cups plus 2 tablespoons all-purpose flour (270 g)
- 1 teaspoon baking soda
- 1/2 teaspoon salt
- 2/3 cup unsalted butter, melted and slightly cooled (151 g)
- 1/3 cup granulated sugar (66 g)
- 3/4 cup packed light brown sugar (160 g)
- 1 large egg, at room temperature
- 1 egg yolk, at room temperature
- 2 teaspoons vanilla extract
- 1 cup chocolate chips (170 g), plus extra for topping
For the S’mores Topping
- 6 regular-sized marshmallows, cut in half
- 1 Hershey’s chocolate bar
- 5–6 graham cracker sheets
Ingredient Notes
Butter: Use unsalted butter so you can control the salt level. Allow it to cool slightly after melting before combining it with the egg.
Brown sugar: Light brown sugar contributes moisture, chewiness, and a subtle caramel-like flavor. Pack it firmly into the measuring cup if you are measuring by volume.
Egg and egg yolk: The additional yolk helps create a rich, tender cookie texture. Using room-temperature eggs also makes mixing easier.
Chocolate chips: Semi-sweet chocolate chips provide a nice balance with the sweet marshmallows and cookie dough.
Marshmallows: Regular-sized marshmallows cut in half are easy to distribute across the surface. Keep in mind that marshmallows can melt and spread during baking.
Graham crackers: These add the familiar crunchy, honey-like flavor associated with traditional s’mores. If graham crackers are unavailable, digestive biscuits can be used as an alternative, although the flavor will differ.
How to Make S’mores Cookie Bars
Step 1: Prepare the Baking Pan
Preheat your oven to 175°C (350°F).
Line an approximately 23 × 33 cm (9 × 13-inch) baking pan with parchment paper, leaving some overhang along the sides. This makes it easier to lift out the cookie bars after they have cooled.
Lightly grease the parchment paper if necessary to help prevent sticking.
Step 2: Mix the Dry Ingredients
In a medium bowl, whisk together the all-purpose flour, baking soda, and salt.
Mixing these ingredients separately helps distribute the baking soda and salt evenly throughout the flour, promoting a more consistent texture.
Set the bowl aside while you prepare the wet ingredients.
Step 3: Combine the Melted Butter and Sugars
In a large mixing bowl, combine the melted, slightly cooled butter, granulated sugar, and packed light brown sugar.
Whisk until the mixture looks smooth and the sugars are evenly incorporated.
The melted butter and brown sugar help create the rich, chewy texture that makes these bars taste like a thick chocolate chip cookie.
Step 4: Add the Egg, Egg Yolk, and Vanilla
Add the whole egg, additional egg yolk, and vanilla extract to the butter mixture.
Whisk until smooth and well combined. Scrape down the sides of the bowl if needed.
Make sure the melted butter is not too hot before adding the eggs, as excessive heat can begin cooking them.
Step 5: Add the Dry Ingredients
Gradually add the flour mixture to the wet ingredients.
Use a sturdy spatula or wooden spoon to mix until a soft cookie dough forms. Stop as soon as the flour is incorporated.
The dough should be thick rather than pourable. Avoid overmixing, which can make the finished bars tougher.
Step 6: Fold in the Chocolate Chips
Add the chocolate chips to the dough and fold them in evenly.
Reserve a small handful of chocolate chips for the top if you want the finished bars to look especially chocolatey.
The dough should now be thick, rich, and filled with chocolate chips.
Step 7: Press the Dough into the Pan
Transfer the cookie dough to the prepared baking pan.
Use a spatula or clean hands to press it into an even layer, reaching the corners of the pan.
Try to keep the thickness consistent so the bars bake evenly. Scatter a few reserved chocolate chips over the surface.
Step 8: Add the Graham Crackers and Marshmallows
Break the graham cracker sheets into small pieces and distribute them over the cookie dough.
Add the halved marshmallows across the surface, leaving some space between them because they can expand and spread as they heat.
Break the Hershey’s chocolate bar into pieces and arrange them among the marshmallows. Add a few extra chocolate chips if desired.
Press the toppings gently into the dough so they are less likely to fall off when the bars are cut.
Step 9: Bake the Cookie Bars
Place the pan in the preheated oven and bake for approximately 22–28 minutes, checking toward the earlier end of the range.
The edges should be lightly golden, and the cookie layer should look set. The center may still appear slightly soft, but it should not contain wet, raw dough.
The marshmallows may puff up and develop golden patches. If they brown too quickly, keep an eye on the pan and avoid extending the baking time unnecessarily.
Remember that the bars will continue to firm up as they cool.
Step 10: Cool Before Cutting
Remove the pan from the oven and place it on a heat-safe surface.
Allow the cookie bars to cool in the pan for at least 30–45 minutes. For cleaner slices, let them cool completely.
Use the parchment paper overhang to lift the slab onto a cutting board. With a sharp knife, cut it into 12–16 squares.
For an extra-gooey dessert, you can serve the bars slightly warm. The chocolate will be softer, and the marshmallows will remain tender.
Tips for the Best S’mores Cookie Bars
1. Let the Melted Butter Cool Slightly
Butter that is excessively hot can affect the egg mixture and make the dough greasy. Let it cool until warm but not hot before mixing.
2. Measure the Flour Carefully
Too much flour can make cookie bars dry or cakey. Weighing the flour is the most reliable approach. If using measuring cups, spoon the flour into the cup and level it rather than packing it down.
3. Do Not Overmix the Dough
Mix only until the flour disappears. Gentle mixing helps preserve a tender, chewy texture.
4. Distribute the Toppings Evenly
Spread the marshmallows, chocolate pieces, and graham crackers across the surface so each square receives a little of everything.
5. Watch the Marshmallows
Marshmallows can brown quickly and may spread as they melt. Check the bars toward the end of the baking time to prevent the topping from becoming too dark.
6. Allow the Bars to Cool
Warm cookie bars are delicate and can break apart when cut. Cooling gives the cookie base time to firm up and makes serving easier.
7. Use Parchment Paper
Parchment paper helps prevent sticking and makes it much easier to remove the entire slab from the pan.
Common Mistakes to Avoid
Using hot butter: Very hot butter can cook the eggs or produce an overly greasy dough. Let it cool slightly first.
Overbaking the cookie layer: Baking for too long can make the bars dry and hard. Remove them when the edges are golden and the center is set but still soft.
Cutting the bars too early: The chocolate and cookie base need time to firm up. Let the bars cool before slicing if you want neat squares.
Adding too many marshmallows: A generous topping is delicious, but excessive marshmallows can melt into a sticky layer that makes cutting difficult. Use the specified amount and distribute them evenly.
Forgetting to line the pan: Melted marshmallows and chocolate can stick to the baking pan. Parchment paper makes cleanup and removal easier.
Delicious Variations
Peanut Butter S’mores Cookie Bars
Add a few small spoonfuls of peanut butter to the cookie dough before baking. You can also drizzle a little melted peanut butter over the cooled bars for a sweet-and-salty twist.
Double Chocolate S’mores Bars
Use a mixture of semi-sweet and dark chocolate chips, then add extra chocolate pieces on top. This variation is ideal for anyone who enjoys a more intense chocolate flavor.
Graham Cracker Cookie Base
For a stronger graham cracker flavor, crush a few extra crackers into small crumbs and mix them into the cookie dough. Keep the total amount of flour consistent if making significant ingredient changes, since additional dry ingredients can affect the texture.
Salted Chocolate S’mores Bars
Sprinkle a small pinch of flaky sea salt over the bars immediately after baking. The salt contrasts with the sweetness of the chocolate and marshmallows.
Holiday S’mores Cookie Bars
Use seasonal chocolate pieces or festive sprinkles to adapt the bars for holidays and parties. Add decorations that are suitable for baking, and avoid placing delicate decorations on the hot marshmallows if they may melt.
How to Serve S’mores Cookie Bars
These cookie bars are delicious on their own, but there are several ways to serve them:
- Slightly warm: Enjoy them while the chocolate is still soft.
- With vanilla ice cream: The cold, creamy texture contrasts beautifully with the rich cookie bars.
- With a glass of milk: A classic pairing for chocolate chip cookies and marshmallows.
- As a party dessert: Arrange the cooled squares on a platter for easy serving.
- With hot chocolate or coffee: Serve them as an afternoon treat or cozy evening dessert.
If you want a more dramatic presentation, warm an individual square briefly before serving. Heat it in short intervals and check carefully, as the marshmallows can become very hot.
How to Store S’mores Cookie Bars
At Room Temperature
Once completely cooled, place the bars in an airtight container. They generally keep well for about 3–4 days in a cool, dry place.
If stacking them, place parchment paper between the layers to help prevent the marshmallows and chocolate from sticking.
In the Refrigerator
Refrigeration is optional for the basic recipe. If you prefer firmer bars, you can refrigerate them in an airtight container, although the cookie layer may become firmer.
Allow refrigerated bars to sit at room temperature briefly before serving, or warm an individual piece gently.
In the Freezer
For longer storage, wrap the cooled bars individually or separate layers with parchment paper and place them in a freezer-safe container.
Freeze for approximately 2 months for best quality. Thaw at room temperature before serving.
The marshmallow texture may change slightly after freezing and thawing, but the bars should still be enjoyable.
Frequently Asked Questions
What are S’mores Cookie Bars?
S’mores Cookie Bars are a baked dessert inspired by traditional s’mores, which combine chocolate, marshmallows, and graham crackers. This version uses chocolate chip cookie dough as the base and bakes everything together in one pan.
Can I make these cookie bars without graham crackers?
Yes. Digestive biscuits can be used as a substitute, although they have a different flavor and texture. Other crisp, lightly sweet biscuits may also work.
Can I use mini marshmallows instead of regular marshmallows?
Yes. Mini marshmallows can be scattered across the dough in place of halved regular marshmallows. Use a similar overall quantity and watch them closely because smaller marshmallows can brown quickly.
Why are my cookie bars too hard?
Overbaking is a common cause. Too much flour can also make the cookie base firm. Measure carefully and remove the bars when the edges are golden and the center is set.
Why are my cookie bars difficult to cut?
The marshmallows and melted chocolate can remain sticky while warm. Let the bars cool before cutting, and use a sharp knife. Wiping the blade between cuts can help keep the edges neat.
Can I prepare the dough ahead of time?
Yes. You can prepare the cookie dough in advance and refrigerate it in a covered container. Allow it to soften enough to press evenly into the pan. The baking time may vary if the dough is cold.
Can I use a different chocolate bar?
Yes. A similar milk chocolate or semi-sweet chocolate bar can replace the Hershey’s bar. The sweetness and flavor will vary depending on the chocolate you choose.
How do I make the bars extra gooey?
Serve them slightly warm after allowing them to cool enough to hold their shape. You can warm individual squares briefly before serving, but avoid overheating them because the marshmallows become extremely hot.
Final Thoughts
These S’mores Cookie Bars bring together the best parts of chocolate chip cookies and classic campfire s’mores. The buttery, chewy cookie base, melted chocolate chips, crunchy graham crackers, and soft marshmallows create a dessert that is both nostalgic and satisfying.
They are easy to prepare in one pan and ideal for sharing at parties, family gatherings, summer cookouts, or cozy nights at home.
For the best results, measure the ingredients accurately, keep an eye on the marshmallows while baking, and let the bars cool before cutting. Serve them slightly warm when you want soft chocolate and gooey marshmallows in every bite.
Recipe Card
Recipe Name: S’mores Cookie Bars
Prep Time: 15–20 minutes
Cook Time: 22–28 minutes
Cooling Time: 30–45 minutes
Total Time: Approximately 1 hour 10 minutes to 1 hour 30 minutes
Yield: 12–16 bars
Oven Temperature: 175°C (350°F)
Pan Size: Approximately 23 × 33 cm (9 × 13 inches)
Ingredients
Cookie dough
- 270 g all-purpose flour
- 1 teaspoon baking soda
- 1/2 teaspoon salt
- 151 g unsalted butter, melted and slightly cooled
- 66 g granulated sugar
- 160 g packed light brown sugar
- 1 large egg, at room temperature
- 1 egg yolk, at room temperature
- 2 teaspoons vanilla extract
- 170 g chocolate chips, plus extra for topping
Topping
- 6 regular-sized marshmallows, cut in half
- 1 Hershey’s chocolate bar
- 5–6 graham cracker sheets
Instructions
- Preheat the oven to 175°C (350°F). Line a 23 × 33 cm baking pan with parchment paper.
- Whisk together the flour, baking soda, and salt in a medium bowl.
- In a large bowl, combine the melted butter, granulated sugar, and brown sugar.
- Add the egg, egg yolk, and vanilla extract. Whisk until smooth.
- Add the dry ingredients and mix until a thick cookie dough forms.
- Fold in the chocolate chips.
- Press the dough evenly into the prepared baking pan.
- Break the graham crackers into pieces and distribute them over the dough.
- Add the halved marshmallows and pieces of chocolate bar. Sprinkle extra chocolate chips on top if desired.
- Bake for 22–28 minutes, until the edges are lightly golden and the center is set.
- Cool in the pan for at least 30–45 minutes before lifting out and cutting into squares.