featured 20499

Chocolate Marshmallow S’mores Cookie Bars

small stack of s'mores cookie bars on wire rack with mini marshmallows and chocolate

These S’mores Cookie Bars are soft, chewy, and packed with gooey marshmallows, melting milk chocolate, and buttery graham cracker crumbs in every bite. They’re an easy, big-batch treat that captures the flavor of summer without a campfire.

With summer in full swing, a s’mores-inspired recipe felt perfect. These cookie bars deliver all the nostalgia of a classic s’more—marshmallow, chocolate, and graham cracker—into a simple pan of bars you can bake at home. They’re straightforward to prepare and great for sharing at picnics, potlucks, or backyard gatherings.

closeup of a s'mores cookie bar on a black wire rack

These bars require an oven but very little hands-on time. The dough comes together quickly, and once it’s pressed into the pan, a short bake time produces a golden, chewy pan of s’mores goodness. The top is finished with a sprinkle of mini marshmallows and a few broken Hershey bar pieces that become warm, melty pockets of chocolate.

stack of s'mores cookie bars with marshmallows and hershey bars on wire rack

These S’mores Cookie Bars are ideal when you want the flavor of summer without the fuss. They stay soft and chewy after cooling, and the combination of marshmallows and milk chocolate keeps them delightfully gooey. Ready to bake a tray?

author holding a s'mores cookie bar

smores cookie bars on wire rack

S’mores Cookie Bars

Soft, chewy cookie bars stuffed with gooey marshmallows, melty milk chocolate, and the crunch of graham cracker crumbs—everything you love about s’mores in a single pan.
Prep Time
10 mins
Cook Time
30 mins
Total Time
40 mins
Course:
Bars, Dessert
Cuisine:
American, Dessert
Servings:
15

Ingredients

  • 12 Tablespoons (1 & 1/2 sticks) unsalted butter softened to room temperature
  • 1 cup brown sugar
  • 1/2 cup granulated white sugar
  • 1 large egg
  • 1 large egg yolk
  • 1 Tablespoon vanilla extract
  • 1 tsp baking soda
  • 2 tsp cornstarch
  • 1/4 tsp salt
  • 1½ cups all-purpose flour
  • 1/2 cup graham cracker crumbs
  • 2 cups miniature marshmallows divided
  • 1 cup milk chocolate chips
  • 4 fun size Hershey bars broken into pieces

Instructions

  • Preheat the oven to 350°F (175°C). Line a 13×9-inch light metal baking pan with foil, allowing the foil to extend over the edges for easy removal. Spray the foil lightly with cooking spray. Using foil or parchment helps contain any melted marshmallows.
  • In the bowl of a stand mixer fitted with the paddle attachment, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy, about 1 minute. Beat in the egg, then the egg yolk, and finally the vanilla, mixing well after each addition.
  • Add the baking soda, cornstarch, salt, flour, and graham cracker crumbs to the mixer and combine until just incorporated. Fold in 1½ cups of the miniature marshmallows and the milk chocolate chips until distributed throughout the dough.
  • Press the dough evenly into the prepared pan. Scatter the broken Hershey bar pieces over the surface. Bake for 20 minutes, then remove the pan from the oven. Sprinkle the top with the remaining ½ cup of miniature marshmallows and return to the oven for another 5–10 minutes, until the bars are light golden, set around the edges, and the marshmallows are just toasted.
  • Allow the bars to cool completely in the pan before lifting them out using the foil overhang and cutting into squares. Cooling helps the bars set and makes clean slices easier.

Notes

For the best chocolate flavor and melt, milk chocolate chips from reputable brands provide a creamy finish. If you prefer a slightly richer chocolate, swap some or all of the milk chips for semi-sweet.

close up of s'mores cookie bar on a wire rack with marshmallowThese bars are irresistible and perfect for sharing—everyone loves an easy, nostalgic dessert that tastes like summer.

S'mores Cookie Bars photo collage with text

Have a sweet day!

xo, Hayley