1Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13-inch baking dish.
2Mix pumpkin, evaporated milk, sugar, eggs, and pumpkin pie spice together in a bowl. Pour pumpkin mixture into prepared baking dish. Sprinkle cake mix over pumpkin mixture; drizzle with butter. Sprinkle pecans atop butter layer.
3Bake in the preheated oven until a knife inserted in the center comes out clean, about 1 hour.