Preheat oven to 350°F. Lightly grease a 9×13 baking pan with nonstick spray and set aside.
In a large mixing bowl blend the pumpkin, milk, sugar, eggs, and pumpkin pie spice. Combine and pour into your prepared pan.
Sprinkle the entire box of cake mix on top.
Pour your melted butter uniformly on top.
Bake for 45-50 minutes until center is set and edges are browned.
Bake for 45-50 minutes until center is set and edges are browned.