Preheat your oven to 350°F and line two baking sheets with parchment paper.
In a medium bowl, whisk together the flour, baking soda, pumpkin pie spice, and salt. Set aside.
In a large bowl or stand mixer, cream the softened butter, brown sugar, and granulated sugar together until light and fluffy, about 3-4 minutes. Beat in the pumpkin puree, egg, and vanilla extract and mix until smooth.
Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined.
Fold in the graham crackers, mini marshmallows, and ¾ cup of the chocolate chips.
Using a cookie scoop or spoon, drop rounded tablespoons of dough onto the prepared baking sheets, spacing them about 2 inches apart.
Sprinkle the remaining chocolate chips on top of each cookie.
Bake for 14-15 minutes or until the edges are lightly golden and the centers are set.
Cool the cookies on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.
Notes
If you prefer a stronger pumpkin spice flavor, increase the pumpkin pie spice to 2 ½ or 3 teaspoons.
Use a cookie scoop for uniformly sized cookies that will bake evenly.
Don't overbake! The cookies may look slightly underdone in the center, but they'll continue to set as they cool.
Cookies can be stored in an airtight container at room temperature for up to 5 days or frozen for up to 3 months.
You can substitute the chocolate chips with white chocolate chips or a mixture of both for variety.