Preheat oven to 350 degrees F. Line a 13x9 inch baking dish with parchment paper and set aside.
In a large mixing bowl, fold together yellow cake mix, ½ cup melted butter, and 1 egg, until a dough forms.
Press the dough mixture into the bottom of the lined baking dish.
In a large bowl, beat cream cheese, pumpkin pie spice, and vanilla, until smooth. Add pumpkin puree, ½ cup melted butter, 3 eggs, and mix well to combine. Mix in powdered sugar, until combined.
Pour the pumpkin mixture over the dough. Bake for 45 minutes, the center will still be slightly jiggly when the bars are done baking.
Allow the bars to cool completely and chill for 1 hour. Slice and enjoy.