Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine pumpkin puree, evaporated milk, eggs, sugar, vanilla, cinnamon, nutmeg, and salt. Mix until smooth.
Pour the pumpkin mixture into a greased 9x13 inch baking dish.
Evenly sprinkle the dry cake mix over the pumpkin mixture.
Drizzle the melted butter evenly over the cake mix.
Do NOT mix; allow the layers to remain separate.
Bake in the preheated oven for 50-60 minutes, or until the top is golden brown.
Check doneness with a toothpick; it should come out clean.
Let cool slightly before serving.