Preheat the oven to 350°F. Grease a 9x13 baking dish or line it with parchment paper.
In a large mixing bowl, cream the softened butter and sugar together until light and fluffy.
Add the pumpkin puree, eggs, and vanilla extract. Mix until smooth and well combined.
In a separate bowl, whisk together the flour, baking soda, baking powder, cinnamon, ginger, nutmeg, allspice, cloves, and salt.
Add the dry ingredients to the wet ingredients and mix until just combined. Do not overmix.
If using fresh milled flour, let the batter rest for 10 minutes before baking.
Spread the batter evenly into the prepared baking dish.
Bake for 32 to 38 minutes, or until a toothpick inserted in the center comes out clean.
Let the pumpkin bars cool completely before frosting.
To make the frosting, beat the softened cream cheese and butter together until smooth and creamy.
Add the vanilla extract, salt, and powdered sugar. Beat until smooth and spreadable.
Spread the cream cheese frosting over the cooled pumpkin bars.
Slice into bars and serve.