In a large bowl, whisk together the flour, baking powder, salt, cinnamon and pumpkin pie spice. Set aside.
In the bowl of an electric mixer (or using a hand mixer), beat the butter, sugar and brown sugar on medium high speed until light and fluffy, about 3 minutes.
Add the egg yolk, vanilla and pumpkin. Mix until well combined. Scrape down the sides of the bowl as needed.
Add the flour mixture and slowly mix until well combined (no not over-mix).
Cover and chill the dough for at least 2 hours.
Preheat your oven to 350℉ and line a baking sheet with parchment paper.
Remove the cookie dough from the refrigerator. Use a medium cookie scoop to scoop the dough and roll into balls. Roll each cookie dough ball in granulated sugar and place on the prepared baking sheet.
Bake at 350℉ for 12 minutes or until the edges are set and center is soft. Cool cookies. on the pan for a few minutes before transferring to a wire rack to cool completely.
Notes
Store cookies in an airtight container at room temperature for up to 1 week.Chill dough for up to 48 hours. Let the dough sit at room temperature for 10 minutes or until soft enough to scoop.Freeze dough for up to 3 months. Defrost in the refrigerator before scooping and baking.