Preheat oven to 375°F (190°C). Line baking sheets with parchment paper.
In a large bowl, cream together butter, granulated sugar, and brown sugar until light and fluffy. Beat in eggs one at a time, then stir in vanilla extract.
In a separate bowl, whisk together flour, baking soda, and salt. Gradually add to the wet ingredients, mixing until just combined.
Stir in crushed graham crackers and chocolate chunks. Gently fold in mini marshmallows.
Drop by rounded tablespoons onto prepared baking sheets. Place a few extra marshmallows on top of each cookie.
Bake for 10-12 minutes, or until edges are golden brown. Let cool on baking sheets for a few minutes before transferring to a wire rack to cool completely.
Notes
Enjoy these gooey and delicious S'mores Cookies warm!