In a large bowl or bowl of a standing mixer, combine the butter, sugars, pumpkin, egg and vanilla.
Beat until fluffy.
In a separate bowl whisk together the flour, baking powder, baking soda, salt, cinnamon, nutmeg and cream of tartar.
Slowly add dry mixture to pumpkin mixture.
Mix until combined but do not over mix.
Cover and refrigerate 1 hour.
Preheat oven to 350 degrees F.
Combine 1/2 c. sugar and 1 t. cinnamon in a small bowl.
Scoop the cookie dough and roll into balls.
Drop the balls in the sugar/cinnamon mix and roll around until the ball is covered.
Once the balls are on the ungreased cookie sheet, flatten with the bottom of a small glass.
Bake 10 minutes.
Can be stored in an airtight container for several days.