Step 1: Prepare the Oven and Baking Sheets
Preheat oven to 350°F (175°C).
Line two baking sheets with parchment paper.
Step 2: Mix Dry Ingredients
In a medium bowl, whisk together flour, baking powder, baking soda, cinnamon, ginger, nutmeg, and salt. Set aside.
Step 3: Mix Wet Ingredients
In a large bowl, combine brown sugar and vegetable oil until smooth.
Stir in pumpkin puree, egg, and vanilla extract until fully incorporated.
Step 4: Combine Wet and Dry Ingredients
Gradually fold the dry ingredients into the wet mixture, mixing gently until just combined. Avoid overmixing.
Step 5: Bake the Cookies
