In a large mixing bowl, whisk together all-purpose flour, pumpkin pie spice, ground cinnamon, baking soda, and salt until evenly blended.

In a stand mixer, beat together softened unsalted butter, brown sugar, and granulated sugar for 1-2 minutes until light and fluffy. Add in egg yolk and vanilla extract, mixing well until fully incorporated.

Gently stir in pumpkin puree into the wet ingredients, ensuring a smooth and homogenous mixture.

Gradually add the dry ingredient mixture to the wet ingredients, mixing until just combined. Fold in rolled oats.

Cover the bowl with plastic wrap and refrigerate the dough for about 30 minutes.

Preheat your oven to 350°F (180°C) and line your baking sheets with parchment paper.

Scoop spoonfuls of the dough onto the baking sheets, spacing them about 2 inches apart. Flatten each ball slightly.

Bake for 9-12 minutes or until edges are lightly browned and tops are set. Let cool for a few minutes before transferring to a wire rack.