In a large bowl, whisk together the flour, baking powder, salt, and cinnamon. Set aside.
With your mixer on medium, mix together the butter and sugar until light and fluffy.
Mix in the egg yolk, then vanilla, then pumpkin until well combined.
Slowly mix in the flour mixture until well combine, with your mixer set to low. Scrape down the paddle and the sides of the bowl as necessary.
Preheat your oven to 350 degrees and refrigerate the cookie dough for 20 minutes.
In a separate bowl mix together the sugar, cinnamon and pumpkin pie spice.
Roll the dough into one inch sized balls. Roll in sugar. Place on a parchment lined baking sheet or silicon mat and press down slightly. Space the cookies about two inches apart.
Bake for 10 minutes, rotating the pan halfway through the baking.
Let cool on the pan for about 2-3 minutes before moving to your cooling rack to cool completely.