Whisk together flour, baking powder and salt in a medium sized mixing bowl. Set aside.
In a large bowl or your stand mixer at medium speed, beat butter and sugar together until light and fluffy; 1-2 minutes.
Beat in pumpkin, egg and vanilla until smooth; about 1-2 minutes.
Stir in the flour, baking powder and salt, just until combined.
Cover and refrigerate for at least 1 hour or up to overnight.
Preheat 350 degree oven. Line 2 baking sheets with silicone or parchment paper.
Pour granulated sugar into a shallow dish.
Roll 2 tablespoons of dough into a ball with your hands (dough will be slightly sticky), then roll in the sugar mixture. Repeat with all of the cookie dough. Arrange 1-2 inches apart on the prepared baking sheet and press down lightly with your palm. Bake for 8-10 minutes or until cookies are golden on top and lightly browned on the bottom.
Cool for a few minutes on the baking sheet, then transfer to a wire rack to cool completely.
You can add a little pumpkin spice or ground cinnamon to the dough or to the sugar coating if you want that flavor. Store cookies in a plastic bag at room temperature for 4-5 days. Freeze in a freezer bag for up to 6 months.