Preheat oven to 350°F. Grease a 13-9 baking dish with nonstick spray.

In a large bowl (or stand mixer), mix together the cake mix, pumpkin puree, pumpkin pie spice, salt, vanilla, and eggs until well combined.

Pour into a prepared baking dish, bake in preheated 350°F oven for 30 - 35 minutes or until a toothpick inserted in center comes out clean. Cool for 5 - 10 minutes.

Mix together the evaporated milk, sweetened condensed milk, and whole milk or cream. Poke holes into the top of the cake with a fork, pour mixed milks over cake. Place cake in the refrigerator for at least 30 minutes (and up to an hour for best results), to allow to chill and absorb the milk mixture.

Once completely cooled, frost the cake with vanilla frosting. Dust with grated pumpkin pie spice. Cut and serve.