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

In a medium bowl, whisk together the all-purpose flour, pumpkin pie spice, ground cinnamon, baking soda, and salt.

In your mixer, combine the softened unsalted butter, brown sugar, and granulated sugar. Beat for 1 to 2 minutes until smooth, then add the egg yolk and vanilla extract.

Add the pumpkin puree to the wet mixture, blending until creamy. Squeeze out any excess moisture beforehand.

Gradually add the dry ingredient mixture to the wet mixture, stirring gently. Fold in the old-fashioned rolled oats.

Cover dough tightly with plastic wrap and refrigerate for at least 30 minutes.

Scoop the dough onto the prepared baking sheets. Flatten each dough ball slightly and bake for 9 to 12 minutes until edges are lightly browned.

Let cookies rest on the baking sheet for about 5 minutes, then transfer to a wire rack to cool completely.