Chewy S’mores Cookie Bars

Thick, chewy, and extra gooey — these s’mores cookie bars capture everything you love about the classic campfire treat. The cookie dough includes crushed graham crackers for that unmistakable s’mores flavor, and the bars are filled with a generous layer of milk chocolate topped with marshmallow fluff for a melting, indulgent center.

These s’mores cookie bars are perfect for summer, but they’re good any time of year. The dough is similar to classic blondie or chocolate chip cookie dough, with some of the flour replaced by finely crushed graham crackers so each bite tastes like a s’more. After pressing the dough into the pan, a layer of milk chocolate bars is placed over the base, followed by a thick spread of marshmallow fluff. The remaining dough is dotted on top, and the whole pan bakes until the edges are golden and the marshmallow becomes delightfully gooey.

The finished bars are thick, chewy, and generously filled with chocolate and marshmallow. Serve them warm for an ooey-gooey experience, or let them cool for cleaner slices. Either way, they’re irresistible.

Making S’mores Cookie Bars

Start by preparing the graham cookie dough, then assemble and bake. The steps below are straightforward and work well when done by hand — no mixer required.

1. Whisk together melted unsalted butter, brown sugar and granulated sugar until the butter is fully incorporated and no longer sitting on top of the sugars.
2. Add the whole egg, an extra egg yolk and vanilla extract; whisk until combined. The extra yolk keeps the bars chewy.
3. Stir in the all-purpose flour and salt until just combined; the salt balances the sweetness.
4. Fold in the crushed graham crumbs until evenly distributed through the dough.

Once the dough is ready, assemble the bars in an 8×8 inch (20×20 cm) lined pan.

1. Reserve about 1 cup of dough for the top layer and set aside.
2. Press the remaining dough evenly into the bottom of the prepared pan to form a base.
3. Arrange an even layer of milk chocolate over the dough. Use full chocolate bars broken as needed to cover the surface with little to no gaps.
4. Spoon and spread about 1½ cups of marshmallow fluff over the chocolate layer. Placing the chocolate under the fluff helps the bars slice cleanly later.
5. With the reserved dough, scoop small portions (about 1–2 tablespoons each), flatten them into discs, and place them across the marshmallow layer to cover as much as possible. It’s fine if some marshmallow shows through.

Bake the bars at 350°F (180°C) for about 30–35 minutes. The top should turn golden brown. If any marshmallow is exposed it will puff and create pockets and pools of ooey-gooey marshmallow; if fully covered by dough, the marshmallow will remain a more even layer in the center.

Mores S’mores Treats to Love: try the same flavors with a graham crust or swap in golden cereal crumbs for a different take on this classic combination.