Preheat oven to 375 degrees F.
Whisk together flour, baking soda, salt and cinnamon in a medium bowl. Set aside.
In a large bowl, cream together butter and sugars with an electric mixer until fluffy, about 2-3 minutes.
Incorporate vanilla then add eggs one at a time, beating well after each addition.
Gradually beat in flour mixture. Fold in dark chocolate chunks and 1 cup of marshmallows
Lay out graham crackers on a large rimmed baking sheet leaving no gaps between them. Using an ice cream scoop, place balls of cookie dough on the graham crackers. Press out the dough to spread it out, but don’t worry about gaps as the dough will spread and fill the gaps in the oven.
Bake for 5 minutes then press Hershey pieces and 1/4 cup marshmallows on top. Bake for 5-7 more minutes.
Cool bars in pan. Cut through the cookie layer into squares, making sure to cut where the graham crackers meet. Store at room temperature in an air-tight container.