Preheat oven to 350°F (175°C) and line baking sheets with parchment paper or silicone mats.

1. In a medium bowl, whisk together flour, graham cracker crumbs, baking soda, and salt.
2. In a large bowl, cream butter and sugars until light and fluffy. Add eggs and vanilla; beat until combined.
3. Gradually add the dry mixture to the wet ingredients, mixing until just combined.
4. Fold in chocolate chips and mini marshmallows.
5. For cracker-based cookies: Place graham cracker squares on prepared sheets and scoop dough on top. For crumb-based: Scoop dough directly onto sheets.
6. Press extra marshmallows on top if desired.
7. Bake for 9–12 minutes, or until edges are golden and centers look set but soft.
8. Press a Hershey’s chocolate piece on top while warm if using. Let cool 2–3 minutes on the sheet, then transfer to a wire rack.