Make cookie dough: In a large bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.
Add egg and vanilla: Beat in the egg and vanilla extract until well combined.
Combine dry ingredients: In a separate bowl, whisk together the flour, baking soda, and salt.
Combine wet and dry ingredients: Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Add pumpkin and spice: Stir in the pumpkin puree and pumpkin pie spice until evenly distributed.
Chill dough: Cover the dough and refrigerate for at least 1 hour, or preferably overnight. This chilling is crucial for preventing spreading and enhancing the flavor.
Preheat oven and prepare coating: Preheat oven to 375°F (190°C). Line baking sheets with parchment paper. In a small bowl, combine the granulated sugar and cinnamon for the coating.
Shape cookies: Scoop or drop rounded tablespoons of dough onto the prepared baking sheets, leaving some space between each cookie.
Coat with cinnamon sugar: Roll each cookie dough ball in the cinnamon sugar mixture, ensuring it's fully coated.
Bake: Bake for 10-12 minutes, or until the edges are lightly golden and the centers are still slightly soft.
Cool: Let the cookies cool on the baking sheets for a few minutes before transferring them to a wire rack to cool completely.