Toasted S’mores Cookie Bars

Sophia Kim
Sophia Kim
Published: July 28, 2026
Tags: Marshmallow, Chocolate Dessert, Summer Dessert, Cookie Bars, Bake Sale, Graham Crackers, S'mores, National S’mores Day

S’mores Cookie Bars

Buttery graham cookie bars layered with melted chocolate and toasted marshmallows bring campfire flavor to an easy shareable dessert.

Prep Time:25 minCook Time:30 minTotal Time:55 minServings:16Difficulty:Easy

These cookie bars capture the best parts of a campfire s’more in a dessert that can be sliced and shared. Graham cracker crumbs flavor the buttery base, while pieces of milk chocolate melt into pockets throughout the center.

The dough is baked in two stages so the marshmallows toast without disappearing. A short head start sets the cookie layer; then chocolate and marshmallows go on top for the final minutes under close watch.

Use standard-size marshmallows cut in half rather than miniature ones. Their broad surfaces bronze attractively and leave a soft center, giving each square the stretchy toasted finish expected from a classic s’more.

The bars need time to cool before cutting because both the chocolate and marshmallow layer are fluid straight from the oven. Serve them slightly warm for the softest texture or at room temperature for tidy picnic-ready squares.

Nutrition (per serving)

Calories:290 kcal
Protein:3 g
Carbs:43 g
Fat:13 g

Directions

  1. 1
    Square baking pan lined with parchment paper

    Heat the oven to 350°F. Line an 8-inch square metal pan with parchment, leaving an overhang on two sides, and lightly butter the exposed pan.

  2. 2
    Dry graham cookie ingredients mixed in a bowl

    Whisk the graham cracker crumbs, flour, baking powder, and salt in a medium bowl until evenly combined.

  3. 3
    Butter and brown sugar creamed in a mixing bowl

    Beat the softened butter and brown sugar in a large bowl for 2 minutes until creamy and slightly lightened.

  4. 4
    Graham cookie dough mixed until no flour streaks remain

    Beat in the egg and vanilla until smooth, then stir in the dry ingredients just until no floury streaks remain.

  5. 5
    Cookie dough pressed evenly into the lined pan

    Press the dough evenly into the prepared pan, using a flat-bottomed cup to make a level, compact layer.

  6. 6
    Golden baked graham cookie base in the pan

    Bake for 18 to 20 minutes, until the edges are golden and the center looks set but remains soft.

  7. 7
    Chocolate and marshmallows arranged over the hot cookie base

    Arrange the chocolate squares over the hot base, then top with the marshmallow halves cut-side down and scatter the graham cracker pieces between them.

  8. 8
    Puffed marshmallows and softened chocolate in the pan

    Return the pan to the oven for 5 to 7 minutes, until the chocolate softens and the marshmallows puff.

  9. 9
    S’mores cookie slab with deeply toasted marshmallows

    Broil 6 inches from the heat for 30 to 60 seconds, watching continuously, until the marshmallow tops are deeply toasted.

  10. 10
    Cooled s’mores cookie bars cut into sixteen squares

    Cool in the pan for 45 minutes, lift out with the parchment, and cut into 16 squares with a lightly greased knife.

Ingredients

  • Graham Cracker Crumbs:1 1/2 cups
  • All-Purpose Flour:1 cup
  • Baking Powder:1/2 tsp
  • Kosher Salt:1/2 tsp
  • Unsalted Butter, Softened:3/4 cup
  • Packed Light Brown Sugar:3/4 cup
  • Large Egg:1
  • Vanilla Extract:1 tsp
  • Milk Chocolate Bars, Broken Into Squares:8 oz
  • Standard Marshmallows, Halved Crosswise:12
  • Graham Crackers, Broken Into Bite-Size Pieces:2

Tips & Notes

  • A metal pan gives the bars firmer golden edges than a glass pan.
  • Freeze the chocolate squares for 10 minutes before topping if the kitchen is very warm.
  • For clean cuts, wipe and lightly grease the knife between slices.