1. Preheat oven to 350°F (175°C) and line two baking sheets with parchment paper.

2. In a large mixing bowl, cream together butter, peanut butter, granulated sugar, and brown sugar until light and fluffy (2–3 minutes).

3. Beat in the egg and vanilla extract until fully combined.

4. In a separate bowl, whisk together flour, baking soda, and salt. Gradually mix dry ingredients into the wet mixture.

5. Fold in chocolate chips and graham cracker pieces.

6. Scoop about 2 tablespoons of dough per cookie onto the baking sheets and flatten slightly.

7. Bake for 8 minutes, remove from oven, and press 4–5 mini marshmallows into each cookie.

8. Return to oven for another 3–4 minutes until edges are golden and marshmallows are toasted.

9. Let cool on pan for 5 minutes before transferring to a wire rack.

10. Optional: Drizzle with melted chocolate and sprinkle extra graham cracker crumbs.