Preheat the oven to 350℉. Spray a 9x13-inch pan with nonstick spray.
In a large bowl, whisk together the pumpkin, evaporated milk, eggs, sugar, spice and salt. Pour into the prepared pan. Sprinkle the dry cake mix evenly on top of the pumpkin mixture. Then sprinkle the pecans on top of the cake mix. Pour the melted butter evenly over the mixture. No need to stir anything around.
Bake for 50 to 55 minutes. Serve warm topped with whipped cream or Cool Whip.