01 - Preheat the oven to 350°F and line two baking sheets with parchment paper.
02 - Whisk together flour, oats, baking soda, salt, and pumpkin pie spice in a medium bowl.
03 - Beat butter, granulated sugar, and brown sugar in a large bowl until light and fluffy.
04 - Mix in egg, pumpkin puree, and vanilla extract until well combined.
05 - Gradually add dry ingredients to wet mixture, mixing just until combined.
06 - Gently fold in raisins and nuts if using.
07 - Drop rounded tablespoons of dough onto prepared sheets, spacing 2 inches apart.
08 - Bake for 11 to 13 minutes until edges are set and centers appear slightly underbaked.
09 - Let cool on baking sheets for 5 minutes, then transfer to wire rack.