Spray a 9 x 13-inch baking dish with nonstick cooking spray
Pour the entire can of crushed pineapple (including juice) and cherry pie filling into the baking dish. Evenly sprinkle the cake mix over the top of pineapples and cherry pie filling.
Pour melted butter evenly on top of all of the cake mix. Make sure it is evenly poured so all the cake mix will bake correctly.
Bake for 40-45 minutes, or until the fruit starts to bubble up, and the edges of the cake turn golden.