Preheat the oven to 350°F and lightly spray a 9x13-inch baking dish with nonstick cooking spray.
In a large bowl, whisk the pumpkin, milk, and eggs together until smooth. Add the sugar, pumpkin pie spice, and salt. Mix well. Add about 1/2 of the dry yellow cake mix to the batter and mix well.
Pour the batter into the greased dish. Sprinkle with the remaining dry cake mix over the batter. Sprinkled with the chopped pecans. Drizzle the melted butter over.
Bake for 55 to 60 minutes or until the edges are brown and the cake is set. (The toothpick test won't work well with a cake that's this dense.) Allow to cool before serving. Served at room temperature or just warm with a scoop of vanilla ice cream.