Preheat oven to 350 degrees.Spray 13 x 9 baking dish with non stick spray
Pour pineapple and juice into the dish and spread to cover the bottom of the dish.
Cover the pineapple with the cake mix making sure all of the pineapple is covered.
You can melt the butter or just slice it and then top the cake mix with the butter, your choice.
Bake for 40 - 50 minutes or until fruit is bubbly and top is golden.
Notes
If you use canned fruit do not drain the fruit, add the entire can into the baking dish.You can double the amount of canned fruit if you like. You can add chopped nuts and or coconut.Mixing and matching of flavors is an added bonus. Try a chocolate cake mix over cherry pie filling or a yellow cake mix over canned peaches.