Preheat oven to 375 degrees. Line 9x9 pan with parchment paper.
In a medium bowl combine the flour, graham cracker crumbs, baking soda, salt. Whisk together.
In a separate larger bowl beat together the butter, sugar, brown sugar and vanilla until creamy.
Add the eggs one at a time, beating well after each addition.
Slowly beat in the flour mixture until smooth.
Stir in the chocolate chips.
Press into the pan.
Bake 20 minutes and remove.
Add chocolate pieces and marshmallows to cover top and return to the oven 5 minutes or until lightly browned.
Cool and cut.