Preheat the oven to 350 degrees F. Grease a mini-muffin pan.

Sift flour, cocoa powder, baking soda and salt into a bowl; set aside. Cream the butter and sugars until well combined and fluffy. Scrape down the bowl. Slowly beat in the eggs one at a time and then add in the vanilla. Mix until well combined. Add the dry ingredients to the wet ingredients along with chocolate chips and mix until just combined.

Fill each mini-muffin tin about 3/4 of the way full (no specified amount because tin-sizes vary). Break up graham crackers into large pieces and put a piece into each muffin tin. Place 3 or 4 mini marshmallows on top of the cookie dough. Bake for 11-15 minutes. Cool for 5 minutes in pan and then transfer to a cooling rack to finish cooling.