Start by preheating your oven to 350°F, and grease or line a 9x13 baking dish with parchment paper. Grab a large mixing bowl and add the pumpkin, evaporated milk, eggs, sugar, pumpkin pie spice and salt. Whisk it together until combined thoroughly.
Add the pumpkin mixture to the baking sheet. Evenly pour the cake mix on top of the mixture and make sure it’s completely covered.
Melt the butter on the stove or in the microwave and evenly pour it on top of the cake mix topping, covering as much of the top as possible. Chop up the pecans and sprinkle them on top of the cake.
Pop the cake in the oven, and bake for 50-60 minutes, or until the batter is fully cooked through and the topping is golden brown. Insert a toothpick in the center of the cake, and if it comes out clean it’s ready! Let the cake cool completely, slice and serve with whipped cream.