Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans or one 9x13-inch baking pan.
In a medium bowl, whisk together the flour, baking powder, baking soda, pumpkin pie spice, and salt. Set aside.
In a large bowl, combine the pumpkin puree, granulated sugar, brown sugar, and vegetable oil. Mix until well blended.
Beat in the eggs one at a time, then stir in the milk.
Gradually add the dry ingredients to the pumpkin mixture, mixing until just combined. Don't overmix!
Pour the batter into the prepared pan(s) and smooth the top with a spatula.
Bake for 30-35 minutes for round cakes or 35-40 minutes for a 9x13-inch cake, until a toothpick inserted into the center comes out clean.
Cool in the pan for 10 minutes, then remove and cool completely on a wire rack before frosting.