Preheat your oven to 350°F and prepare the 9x13 inch baking dish by buttering or greasing it.

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

In a large bowl, whisk together the eggs, granulated sugar, vegetable oil, pumpkin puree, maple syrup, and vanilla extract until smooth.

Add the dry ingredients to the pumpkin mixture, stirring until just combined.

Spread the batter evenly into the prepared baking pan and smooth the top.

Bake in the preheated oven for about 30 to 35 minutes, or until a toothpick inserted in the center comes out clean.

Once baked, allow the bars to cool completely in the pan on a wire rack.

For the frosting, cream together the softened cream cheese and butter in a large bowl until smooth.

Add the vanilla extract and a pinch of salt to the cream cheese mixture, and mix until incorporated.

Gradually mix in powdered sugar until you reach your desired frosting consistency.

Once the bars are completely cool, spread the frosting generously over the top.

Slice the bars into rectangles or squares for serving and enjoy at room temperature or slightly chilled.