Preheat oven to 350 degrees. Line two large cookie sheets with parchment paper (the marshmallows will melt and stick to the pan, so lining the pans with parchment is very important).
In the bowl of a stand mixer fitted with the paddle attachment, cream together the butter, sugar, and brown sugar. Incorporate the egg followed by the vanilla. In a bowl, stir together the flour, graham cracker crumbs, pinch of cinnamon, baking powder, and salt. Turn the stand mixer on low and gradually add the dry ingredients, mixing just until it is all combined and forms a dough. Mix in the chocolate chips and marshmallows.
Using a medium cookie scoop (about 1 ½ tablespoon-sized balls), scoop the dough onto the prepared cookie sheets, 12 per sheet. Flatten the dough slightly with the palm of your hand.
Bake the cookies in the preheated oven for 10-12 minutes, being careful not to over bake.