Preheat your oven to 350°F. Line a baking sheet with parchment paper.
In a large bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy.
Beat in the pumpkin puree, egg, and vanilla extract until well combined (add the orange food coloring into this step if you plan to use it).
In a separate bowl, whisk together the flour, baking soda, pumpkin pie spice, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Do not over mix.
Gently fold in the chocolate chips, mini marshmallows and graham cracker pieces.
Using a small cookie scoop or spoon, drop rounded tablespoons of dough onto the prepared baking sheet, spacing them about 2 inches apart.
Top each cookie dough ball by pressing in a few extra marshmallows, chocolate chips and/or pieces of graham crackers into the top of each one.
Bake in the preheated oven for 12 to 14 minutes, or until the edges are golden but the center is still soft.
Allow the cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.
Serve the pumpkin s'mores cookies at room temperature.