Preheat oven: Set your oven to 350°F (175°C) and line 2 baking sheets with parchment paper.

Mix dry ingredients: In a medium bowl, whisk together the all-purpose flour, pumpkin pie spice, baking powder, baking soda, and salt.

Combine wet ingredients: In a separate large bowl, blend together the vegetable oil, brown sugar, granulated sugar, beaten egg, pumpkin puree, and vanilla extract until smooth.

Combine mixtures: Gently fold the dry ingredients into the wet ingredients until just combined.

Prepare sugars: Pour the granulated sugar and powdered sugar into two separate small bowls.

Form dough balls: Take about 1 tablespoon of cookie dough, drop it into the granulated sugar, and toss to coat.

Coat in powdered sugar: Place the dough ball in the bowl of powdered sugar and toss to coat it evenly.

Place on baking sheets: Arrange the coated dough balls on the lined baking sheets, spacing them about 2 inches apart.

Bake cookies: Slide the baking sheets into the preheated oven and bake for 9-10 minutes.

Cool them down: Let the cookies cool on the baking sheets for about 3 minutes, then transfer to a wire rack to cool completely.