Step 1: Oven and Pan Preparation. Preheat your oven to 350°F (175°C). Line two large baking sheets with parchment paper or silicone baking mats to prevent sticking and ensure even browning.
Step 2: Creaming Butter and Sugars. In a large mixing bowl, beat together the softened butter, granulated sugar, and brown sugar until the mixture is light and fluffy. This should take about 2 to 3 minutes using an electric mixer.
Step 3: Adding Wet Ingredients. Add the pumpkin puree, egg, and vanilla extract to the butter mixture. Beat on medium speed until well combined. Don’t worry if the mixture looks slightly curdled at this stage; it will smooth out once the dry ingredients are added.
Step 4: Combining Dry Ingredients. In a separate medium bowl, whisk together the all-purpose flour, baking soda, cinnamon, pumpkin pie spice, and salt. Gradually add these dry ingredients to the wet mixture, stirring until just combined.
Step 5: Folding in Oats and Extras. Gently fold in the rolled oats and chocolate chips (if using) with a spatula. Ensure the oats are evenly distributed throughout the dough without overworking it.
Step 6: Scooping and Baking. Drop rounded tablespoons of dough onto the prepared baking sheets, spacing them about 2 inches apart. Bake for 10 to 12 minutes, or until the edges are lightly golden. Allow the cookies to cool on the pan for 5 minutes before transferring them to a wire rack.