Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a large mixing bowl, beat room-temperature unsalted butter, brown sugar, and granulated sugar until light and fluffy (3-4 minutes).

Add pumpkin puree, egg, and vanilla extract to the mixture and blend until smooth (about 2 minutes).

In a separate bowl, whisk together flour, baking soda, pumpkin pie spice, and salt. Slowly mix it into the wet ingredients until just combined.

Fold in chocolate chips, mini marshmallows, and crushed graham crackers gently with a spatula.

Drop heaping portions of dough onto the prepared baking sheet, spacing them 2 inches apart.

Press extra chocolate chips, marshmallows, and graham cracker pieces on top of the cookie dough balls.

Bake for 12-14 minutes, until edges are golden brown and centers remain soft.

Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack.