Preheat your oven to 350°F (175°C) and grease a 9x13 inch baking pan.
In a large bowl, whisk together the pumpkin puree, granulated sugar, brown sugar, and vegetable oil until smooth.
Add the eggs one at a time, mixing well after each addition.
In a separate bowl, combine the flour, baking soda, baking powder, cinnamon, nutmeg, ginger, and salt.
Gradually add the dry ingredients to the pumpkin mixture, stirring until just combined.
Pour the batter into the prepared baking pan and spread evenly.
Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
Let the bars cool completely in the pan on a wire rack.
While cooling, prepare the frosting by beating together cream cheese and butter until creamy.
Gradually add powdered sugar and vanilla extract, mixing until fluffy. Once bars are cooled, spread frosting evenly on top.