Preheat the oven: Preheat oven to 350°F and line a baking sheet with parchment paper.
Cream the butter and sugars: Beat softened butter, brown sugar, and granulated sugar until light and fluffy.
1 cup unsalted butter, ¾ cup brown sugar, ¼ cup granulated sugar
Mix in wet ingredients: Add pumpkin puree, egg, and vanilla; mix until well combined.
½ cup pumpkin puree, 1 large egg, 1 teaspoon vanilla extract
Combine the dry ingredients: Whisk together flour, baking soda, pumpkin pie spice, and salt in a separate bowl.
2 ¼ cups flour, 1 teaspoon baking soda, 1 teaspoon pumpkin pie spice, ½ teaspoon fine salt
Mix wet and dry ingredients: Gradually add dry ingredients to wet ingredients, mixing until just combined.
Fold in mix-ins: Fold in chocolate chips, mini marshmallows, and graham cracker pieces.
1 cup semi-sweet chocolate chips, 1 cup mini marshmallows, 8 graham crackers
Scoop the dough: Drop rounded tablespoons of dough onto baking sheet, pressing extra toppings on top.
Bake the cookies: Bake for 12-14 minutes until edges are golden; cool on baking sheet, then transfer to wire rack.
Serve: Serve pumpkin s'mores cookies at room temperature.