In a medium bowl, whisk together the flour, baking soda, and salt. Set aside.

In a separate bowl, beat the butter and granulated sugar until smooth, then add the brown sugar and beat until creamy.

Add the egg and vanilla to the mixture and beat until well combined. Gradually mix in the dry ingredients until no streaks of flour remain.

Stir in the chocolate chips.

Using a 1 tablespoon measure, scoop out 6 balls of dough. Place a marshmallow chunk on top of one dough ball.

Top each marshmallow with another one-tablespoon-sized dough ball. Seal the edges together and roll the cookie dough ball to hide the marshmallow inside. Repeat to make 12 cookies.

Place the cookies on a plate and break 3 graham cracker sheets into 12 pieces each. Press three small pieces of graham cracker into each dough ball.

Refrigerate the cookie dough balls for 30 minutes as you preheat the oven to 350F.

Space 6 cookie dough balls evenly on a baking sheet, add extra chocolate chips on top of each cookie, and bake for 11-13 minutes until golden brown.

Crush the remaining graham cracker sheet over the warm cookies as they come out of the oven. Let the cookies cool on the sheet to prevent sticking.