Preheat oven to 350F (175C) and line a baking sheet with silpats or parchment paper. Set aside.
In a large mixing bowl add the butter, both sugars, pumpkin, egg, and vanilla extract and stir or whisk until well combined.
In a separate mixing bowl, whisk together flour, pumpkin spice, baking soda, baking powder and salt.
Gradually add dry ingredients to wet and stir until completely incorporated. Stir in the oats and mix until well blended.
Cover and chill the dough for at least an hour. Remove dough when you're ready to bake.
Roll into large balls and place on a baking sheet, leaving at least an inch apart. Bake for 12 minutes.
Allow cookies to cool on a baking sheet for 5-10 minutes before transferring to a cooling rack to cool completely.
Optional - drizzle with powdered sugar glaze or melted white or dark chocolate.