Preheat the oven to 350 degrees. Spray a 9 x 13 pan with baking spray.

In a large bowl combine the pumpkin puree, milk, eggs, sugar, cinnamon, and salt.  Pour the mixture into the prepared pan.

In a medium bowl combine the white cake mix and pumpkin pie spice. 
Sprinkle it over top of the pumpkin mixture, covering completely.  I
used about ¾ of the cake mixture.

Sprinkle the pecans on top of the cake and then pour the melted butter over top.

Bake for 45-50 minutes.  Remove from the oven and cool on a wire rack.