Preheat oven to 375°F and line baking sheets with parchment.
Whisk flour, baking soda, and salt in a medium bowl.
Cream butter and sugars until fluffy, then beat in eggs and vanilla.
Add dry mixture gradually until combined.
Fold in chocolate chips and graham crackers.
Scoop dough with a cookie scoop, place on sheet, leaving space between cookies.
Bake for 8 minutes, then press in marshmallows and extra chocolate chips.
Return to oven for 2–3 minutes until golden.
Cool for 5 minutes on sheet, then transfer to wire rack.