Preheat oven to 350 degrees, spray a 9x9 baking dish with non-stick cooking spray or with butter. Prepare your cake mixture by whisking together the oil, milk, pumpkin puree, granulated sugar, and brown sugar. Slowly mix in the flour, baking soda, baking powder, salt, and pumpkin pie spice. Pour the batter into the baking dish, make sure the batter is spread out and is even.