Preheat the oven to 350°F.
Add the pumpkin puree, brown sugar, evaporated milk, salt, eggs, and half of the pumpkin pie spice to a large mixing bowl. Whisk until everything is well combined.
30 ounces cans pure pumpkin puree, 1 cup light brown sugar, 12 ounces evaporated milk, 1/8 teaspoon salt, 4 eggs, 2 teaspoons pumpkin pie spice
Pour the pumpkin mixture into a greased 9 x 13 inch baking pan and smooth the top with a rubber spatula.
Sprinkle the dry yellow cake mix evenly over the pumpkin layer.
1 box yellow cake mix
Sprinkle the remaining pumpkin pie spice over the cake mix.
Melt the butter in the microwave, then slowly pour it over the top of the cake mix.
1 cup unsalted butter
Scatter the chopped pecans evenly over the top.
1/2 cup chopped pecans
Bake for about 1 hour, or until the top is golden brown.
Serve the Pumpkin Dump Cake warm with whipped cream or a scoop of vanilla ice cream.