Preheat the oven to 350 degrees

Mix together the pumpkin puree and cake mix until thoroughly combined

Grease a 9x13 baking dish with cooking spray and spread the pumpkin batter evenly into the pan

Bake the pumpkin bars at 350 degrees for 20-25 minutes, until a toothpick inserted comes out clean

Allow the pumpkin bars to cool completely before frosting. Make the cream cheese frosting while they are cooling.

Use a kitchenaid or hand mixer to beat together the softened cream cheese and butter until smooth. Add the vanilla, then the powdered sugar a bit at a time, continuing to mix until the frosting is smooth

Frost the pumpkin bars with the cream cheese frosting

Cover and chill in the fridge until ready to serve, then slice into squares of either 12 large or 24 small servings