Preheat oven to 350 degres.

In the bowl of a stand mixer, cream together the butter and sugar until creamy.

Beat in the vanilla and egg until well combined.

In a medium bowl, combine the graham cracker crumbs, flour, baking soda, and salt. Gradually add to the butter mixture until just combined.

Stir in the chocolate chips and marshmallow bits.

Using a medium cookie scoop, drop balls of dough onto a parchment lined baking sheet. Bake for 7 minutes.

Cookies will look slightly underdone, but should set up nicely as they cool.