Great Pumpkin Dessert

1 15 oz can solid pack pumpkin
1 12 oz can evaporated milk
3 eggs
1 c. sugar
4 tsp. pumpkin pie spice
1 pkg. yellow cake mix
3/4 c. butter

Combine first 5 ingredients and transfer into a 9x13 baking pan. Sprinkle with dry cake mix and drizzle with butter. Bake 350 degrees for 1 hour or until a knife inserted near center comes out clean. Serve with ice cream or whipping cream.