Mix together butter, sugar and brown sugar using an electric mixer. Add pumpkin puree, egg, and vanilla and continue to mix until well blended.
In separate bowl, whisk together the flour, baking powder, salt, and pumpkin pie spice.
Gradually add the dry ingredients to the wet ingredients and mix until fully incorporated.
Cover and refrigerate for at least one hour.
Preheat oven to 350degrees. Mix coating ingredients in small bowl.
Form dough into 2 inch balls. Roll into the sugar mixture and set on cookie sheet.
Bake for 14-16 minutes. Let cool on baking sheet for about 5 minutes, then transfer to wire rack to cool completely.