In a large bowl, whisk together flour, baking soda, salt, cinnamon, and pumpkin pie spice. Stir in the oats.
In another bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy.
Add the egg, vanilla extract, and pumpkin purée to the butter mixture and mix until well combined.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Preheat the oven to 350°F. Drop tablespoonfuls of dough onto a parchment-lined baking sheet, spacing them about 2 inches apart.
Bake for 12 minutes or until the edges are lightly browned. Allow to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.