Prepare the Pumpkin Puree: Place the pumpkin puree between layers of paper towels and press to remove excess moisture. Repeat with fresh paper towels as needed until the pumpkin feels drier.

Mix Dry Ingredients: In a medium bowl, whisk together the flour, cinnamon, pumpkin pie spice, baking soda, and salt.

Cream Butter and Sugars: In a large bowl, beat the softened butter, granulated sugar, and brown sugar together on medium speed until light and fluffy.

Add Wet Ingredients: Mix in the egg yolk and vanilla extract until well combined. Then, add the prepared pumpkin puree and mix until incorporated.

Combine Wet and Dry Mixtures: Gradually add the dry ingredients to the wet mixture, mixing on low speed until just combined. Stir in the rolled oats until evenly distributed.

Chill the Dough: Cover the dough and refrigerate for at least 30 minutes to make it easier to handle and to prevent excessive spreading during baking.

Preheat Oven: Preheat your oven to 350°F (175°C) and line baking sheets with parchment paper or silicone baking mats.

Shape and Bake Cookies: Scoop about 1.5 tablespoons of dough per cookie onto the prepared baking sheets, spacing them about 2 inches apart. Slightly flatten each dough ball with your fingers, as these cookies won’t spread much during baking. Bake for 10-12 minutes, or until the edges are lightly browned and the centers appear set.

Cool and Serve: Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.