Preheat your oven to 350°F (175°C).
Cream together the unsalted butter, light brown sugar, and granulated sugar until light and fluffy, about 2-3 minutes.
Add the pumpkin puree, egg yolk, and vanilla extract to the bowl and mix until well incorporated.
In a separate bowl, whisk together the all-purpose flour, baking soda, baking powder, salt, ground cinnamon, ground nutmeg, ground ginger, and ground cloves.
Gradually add the dry mixture to the wet ingredients, mixing just until combined.
Fold in the rolled oats and semi-sweet chocolate chips using a spatula.
Drop the dough onto prepared baking sheets, spacing them about 2 inches apart.
Bake for 10-12 minutes, or until edges are lightly golden.
Let the cookies cool on the baking sheets for about 5 minutes before transferring them to a cooling rack.
