Preheat the oven to 350°F (175°C). Grease a 9x13-inch baking pan.

In a medium bowl, whisk together the flour, baking powder, baking soda, cinnamon, and salt.

In a large bowl, beat the eggs and granulated sugar until well combined. Mix in the vegetable oil and pumpkin puree until smooth.

Gradually add the dry ingredients to the wet ingredients, stirring just until combined. Do not overmix.

Spread the batter evenly into the prepared pan.

Bake for 25 to 30 minutes, or until a toothpick inserted in the center comes out clean.

Let the bars cool completely in the pan before frosting.

To make the frosting, beat the cream cheese and butter together until smooth and creamy. Add the powdered sugar and vanilla extract and beat until light and fluffy.

Spread the frosting evenly over the cooled bars.

Cut into squares and serve.