Preheat oven to 350°F. In a large bowl, beat the pumpkin, evaporated milk, sugar, eggs and pumpkin pie spice together until smooth. Pour this mixture into a greased 13x9-inch baking pan.
Sprinkle the batter with yellow cake mix to cover. Do not mix or stir together!
Drizzle the melted butter over the top. Lastly, sprinkle with the chopped walnuts. Editor's Tip: Toasted nuts add so much to this recipe. A few minutes of toasting provides flavor, color and crunch.
Bake the cake for one hour or until a toothpick inserted into the center comes out clean (a few crumbs are OK). Serve slices of this pumpkin dump cake with ice cream or whipped cream.
