Prepare the Butter: In a large mixing bowl, add softened butter. Using a hand mixer or stand mixer, cream the butter until smooth and creamy. This step ensures the butter is well incorporated, resulting in a smoother dough.

Mix Wet Ingredients: Add the canned pumpkin puree, granulated sugar, brown sugar, vanilla, pumpkin pie spice, cinnamon, salt, and baking powder to the bowl. Mix thoroughly until all ingredients are fully combined and smooth.

Incorporate the Egg: Add the egg to the mixture and blend well. The egg helps bind the ingredients and gives the cookies structure.

Add Flour Gradually: Slowly add the flour to the mixture, mixing well after each addition to prevent clumps. Continue mixing until a soft dough forms.

Chill the Dough: Cover the dough and place it in the refrigerator for at least 1 hour. This step is crucial to prevent the dough from spreading too much during baking and helps the flavors meld together.

Preheat and Prepare for Rolling: Preheat the oven to 350°F (175°C). In a small bowl, mix the sugar, cinnamon, and pumpkin pie spice for rolling the dough.

Form the Cookies: Scoop about 2 tablespoons of dough and form it into a ball. Gently roll each ball in the cinnamon-sugar mix, making sure to coat well.

Bake the Cookies: Place the dough balls on a baking sheet lined with parchment paper. Bake in the preheated oven for 11-13 minutes or until the edges are set but the centers are soft. Remove from the oven and let them cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.