Pumpkin Dessert

1 (15 oz) can solid pack pumpkin
1 (12oz) can evaporated milk
3 eggs
1 cup sugar
4 tsp. pumpkin pie spice
1 box yellow cake mix
3/4 cup butter or margarine, melted
1 1/2 cups chopped walnuts

In a mixing bowl, combine the first 5 ingredients. Transfer to a 9x13 inch pan. Sprinkle with dry cake mix and drizzle with butter. Top with walnuts. Bake at 350 degrees for 1 hour or until knife test is clean. Serve with ice cream or whipped cream.