Preheat oven to 350 degrees.
Lightly grease a 9 X 13 baking dish
Dump pumpkin puree, eggs, evaporated milk, sugar and pumpin pie spice into prepared baking dish.
Stir ingredients together until well blended.
Scrape down sides and spread evenly.
Sprinkle dry cake mix evenly over pumpkin mixture.
Sprinkle with graham cracker crumbs.
Scatter toffee bits over the top.
Drizzle melted butter over all.
Bake 50 to 55 minutes or until cake is lightly browned and tests done with a toothpick. Cool before serving. Refrigerate overnight, if desired.