Preheat oven to 375 degrees. Mix flour, baking soda and salt together. In a mixing bowl, beat butter, shortening and sugars. Add vanilla and eggs, one at a time. Mix well. Add flour mixture and mix until all of the dry ingredients are well incorporated. Stir in the graham cracker pieces. Drop batter by tablespoons - 2 inches apart on a parchment lined baking sheet. Bake cookies for 8 minutes. Remove from oven, push 3-4 pieces of chocolate and 3-4 mini marshmallows into each cookie. Return to oven and bake 4 minutes. Cool.