Chocolate Chip Marshmallow Cookie Bars

These Chocolate Chip Marshmallow Cookie Bars are a twist on traditional s’mores, featuring a buttery graham cracker cookie bar, gooey toasted marshmallows, and melting chocolate chips. They’re the perfect treat to bring back fond campfire memories.

So gather your ingredients, grab a glass of milk, and get ready to indulge in a decadent and fun dessert experience! All without the smoke.

a chocolate chip marshmallow cookie bar cut from the pan.
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The backstory

My s’mores bars aspirations started out first with an adaptation of my mini chocolate chip cookie recipe. I had seen other cookie recipes with graham crackers, so I replaced a cup of flour with ground graham crackers and added marshmallows to the graham cracker cookie batter. I added even more marshmallows on top towards the end of baking, as many s’mores cookies recipes suggest to do.


The result: the graham crackers added too much extra sugar. I got way too much spread from the marshmallows in the graham cracker cookie batter. And the extra marshmallows melted.

Tasty, but a bit too sweet.

flattened smores cookies with melted marshmallows on a baking sheet.

So when I was talking with my friend Angela at Flash in the Pans about making one of her recipes for the reddit 52 week baking challenge (Week 36: Friendship Challenge), and she suggested her Air Fryer S’Mores Brownies, I got excited.

a pan of s'mores brownies.

Because I don’t own an air fryer, I baked the brownies in the oven, using the same temperature and time. Angela recommended browning the marshmallows under the broiler for about one minute.

S’mores perfection! I think they might even have been better on the second day.

Recipe adaptation

The recipe for these chocolate chip marshmallow cookie bars was a combination of my first attempt at chocolate chip marshmallow cookies and Angela’s recipe for s’mores bars. First, baking cookies as bar cookies eliminates the problem of spread that I had with my first chocolate chip marshmallow cookies.

To solve the problem of the marshmallows melting into the batter, I limited the marshmallows to the s’mores inspired top of the graham cracker cookie bars. I again substituted pulverized graham crackers for flour in the cookie bar itself. And I decreased the amount of sugar but browned the butter to give the bar more oomph.

Tips and tricks

Browning butter

Brown butter is simply that – butter that has been browned. Browning gives your butter a nutty flavor.

Tip from the wise quacker: the secret to browning butter is to cook it slowly over medium-low heat, stirring or swirling it as it cooks to keep it from burning. You know it’s done when the popping stops.

browned butter in a pan.

The equipment

You don’t need a stand mixer for this recipe, but I think it helps when beating in the eggs and vanilla.

You also probably could get by without a food processor to pulverize the graham crackers (shown in Panel #1 below) as long as you can crush them finely.

Making the bars

I recommend sifting the flour and other dry ingredients into the graham crackers (shown below in Panel #2), because I always seem to have a clump or two. But you could always just whisk it well.

Four panels showing pulverized graham crackers, dry ingredients, sugar and butter and eggs, and the final batter.

Finally, panels #3 and #4 show the batter after beating in the eggs and vanilla (in panel #3) and then after stirring in the dry ingredients by hand (in panel #4).

Separating eggs is pretty easy, especially when it’s not critical to do it perfectly, like it is for making meringues. To separate the egg, tap the egg against the edge of a small bowl. Use your thumbs to split the shell apart, trying to keep the yolk in one half of the shell. Pass the yolk back and forth between the halves of the shell until most of the white has dropped into the bowl. Use that leftover egg white for making granola or a cocktail like this vodka sour or aperol sour to go with your s’mores bars.

Is it possible to add too many chocolate chips?

the unbaked chocolate chip marshmallow cookie batter in the pan.

Baking the chocolate chip graham cracker cookie bars

When the batter has cooked, it should be slightly browned and pulling away slightly at the edges (Panel #1 below). A toothpick inserted should come out clean, and it should feel slightly firm to the touch. Sprinkle on the broken graham crackers (Panel #2) and then the mini marshmallows (Panel #3).

four panels showing the steps adding the topping to the bars.

Set an oven rack so the pan will sit about 6 to 8 inches from the broiler, and keep a close eye on the doneness of your marshmallows. Panel #4 shows the marshmallows broiled for only 45 seconds.

Add the chocolate chips, cover the pan with aluminum foil, and let the chocolate soften.

Variations and substitutions

  • Use light brown sugar if you don’t have dark brown. Dark brown sugar just has a little bit more molasses in it, giving your cookie bars a slightly richer flavor. You can read more about the difference in sugars here in this great read from Serious Eats.
  • Sub in chopped chocolate or chips of any kind. The topping should take about 4 ounces of whatever chocolate you prefer.
  • Get your indoor s’mores using a kitchen torch or the microwave.


Cool and store the chocolate chip marshmallow cookies at room temperature, either in an air-tight container or wrap the pan in plastic wrap. They’ll keep well for a few days.

For longer storage, the marshmallow topping wouldn’t freeze well, but you could freeze the pan of baked batter after it cools. Just double wrap it tightly and let it come to room temperature before proceeding with the recipe.


What is the history of s’mores?

I read in this history of s’mores in Food and Wine that graham crackers were developed to curb sex drive and just had to share that tidbit with you.

Do I really have to weigh my ingredients?

No. But you will get more consistent results in baking with a scale. And you can get a reliable one for just about $10.

Can I use a kitchen torch to brown the marshmallows instead of the broiler?

Update: December 1, 2022. Yes, it works, although I actually find it easier to use the broiler since I kept setting marshmallows on fire with the torch!

Can I line my pan with parchment paper like I normally do for brownies?

I greased the pan instead of lining it because I was afraid of what the broiler might do to the parchment. Feel free to use parchment if you are using a kitchen torch instead of the broiler.

a pan full of chocolate chip marshmallow cookie bars

Check out some other Ugly Duckling Bakery cookie and brownie recipes like these salted caramel chip chocolate cookies, shortbread Linzer cookies with raspberry filling, chocolate peppermint spritz cookies, brownie crinkle cookies or ube crinkle cookies. Or, for more cookie bars, try:

Love this recipe? Please leave a 5-heart 💜💜💜💜💜 rating in the recipe card below. Let me know how much you loved it, or any problems you had, in the comments section further down.


5 from 1 vote
Category: Dessert
Cuisine: Unspecified
Prep Time: 25 minutes
Cook Time: 35 minutes
Total Time: 1 hour
Servings: 16 bars
Calories: 276kcal
The combination of graham crackers, melted chocolate, and gooey marshmallows in these chocolate chip marshmallow cookie bars will bring back your fond campfire memories. All without the smoke.
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  • Stand or hand mixer, optional
  • Food processor, optional


  • cup (5.3 ounces or 151 grams) unsalted butter plus more for greasing the pan
  • 6 whole graham crackers (or 3.2 ounces or 90 grams graham cracker crumbs)
  • cup (3.0 ounces or 83 grams) bleached all-purpose flour
  • ½ teaspoon salt
  • ½ teaspoon baking powder
  • ¼ teaspoon baking soda
  • ½ cup (3.4 ounces or 96 grams) dark brown sugar
  • 1 large egg
  • 1 egg yolk
  • ½ teaspoon vanilla extract
  • 8 ounces semisweet or bittersweet chocolate chips


  • 2 whole graham crackers, broken into pieces
  • ½ cup mini marshmallows
  • 4 ounces semisweet or bittersweet chocolate chips


  • Preheat the oven to 325°F. Grease an 8 inch or 9 inch square baking pan.
  • Brown the butter by heating it on medium-low in a small pot. The butter will melt and bubble. Turn off the heat when the bubbling stops. The butter should have darkened and smell slightly nutty. Remove from heat and let cool slightly.
    ⅔ cup (5.3 ounces or 151 grams) unsalted butter
  • Pulverize the graham crackers in a food processor or by hand and add it to a medium bowl.
    6 whole graham crackers (or 3.2 ounces or 90 grams graham cracker crumbs)
  • Sift the flour, salt, baking powder, and baking soda into the bowl with the graham crackers and whisk to mix.
    ⅖ cup (3.0 ounces or 83 grams) bleached all-purpose flour, ½ teaspoon salt, ½ teaspoon baking powder, ¼ teaspoon baking soda
  • In the bowl of a stand mixer (or another medium bowl if using a hand mixer or mixing by hand), combine the sugar and brown butter.
    ½ cup (3.4 ounces or 96 grams) dark brown sugar
  • Add in the egg and egg yolk and beat on medium speed for one minute.
    1 large egg, 1 egg yolk
  • Add the vanilla and beat on medium speed for one minute.
    ½ teaspoon vanilla extract
  • Stir in the dry ingredients by hand and then add the chocolate chips and mix.
    8 ounces semisweet or bittersweet chocolate chips
  • Spread the mixture evenly in the prepared pan and bake for 30-35 minutes, until the bars start to brown and pull away from the sides of the pan, a toothpick inserted in the middle comes out clean, and the cookie feels somewhat firm.
  • Take the pan out of the oven and set the oven to broil with a rack 6 to 8 inches from the broiler.
  • While the broiler is heating, add the graham cracker pieces and then the mini marshmallows to the pan.
    2 whole graham crackers, broken into pieces, ½ cup mini marshmallows
  • Broil for 45 to 60 seconds, watching closely, until the marshmallows have achieved your ideal brownness.
  • Remove from the oven, sprinkle on the chocolate chips, and cover with foil for 5 to 10 minutes.
    4 ounces semisweet or bittersweet chocolate chips
  • These chocolate chip marshmallow cookie bars can be stored at room temperature for up to one week.


Feel free to substitute any type of chocolate – chopped or chip – that you like for the s’mores-inspired top of this cookie bar.


Serving: 1bar | Calories: 276kcal | Carbohydrates: 29g | Protein: 3g | Fat: 17g | Saturated Fat: 10g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 4g | Trans Fat: 1g | Cholesterol: 44mg | Sodium: 167mg | Potassium: 160mg | Fiber: 2g | Sugar: 17g | Vitamin A: 275IU | Vitamin C: 1mg | Calcium: 55mg | Iron: 2mg
Love this recipe?Mention @Uglyducklingbakery or tag #uglyducklingbakery!

These s’mores inspired cookie bars were first posted on September 10, 2021. It was last updated on April 27, 2023.

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