Preheat your oven to 350°F (175°C) and grease and line the baking pan with parchment paper.
In a large mixing bowl, combine the pumpkin puree, vegetable oil, and granulated sugar. Mix well with an electric mixer or whisk.
Add the eggs to the mixture and mix until fully combined.
In a separate bowl, sift together the flour, baking powder, baking soda, cinnamon, nutmeg, ginger, and salt.
Gradually combine the dry ingredients with the wet ingredients, stirring until just mixed. Do not overmix.
Pour the batter into the prepared baking pan and spread evenly.
Bake in the preheated oven for about 25 minutes or until a toothpick inserted in the center comes out clean.
While the pumpkin bars are baking, prepare the cream cheese frosting by beating together the softened cream cheese, softened butter, vanilla extract, and powdered sugar in a mixing bowl until smooth and creamy.
Once the bars have cooled completely, spread the cream cheese frosting evenly on top.
Cut into 12 bars and serve.