pre heat oven to 350 degrees. In a 13x9x2 cake pan, dump both cans of cherry pie filling in. Then dump both cans of drained pineapple on top. If you want, you can mix the two up a little in the pan. Spread the dry yellow cake mix over the fruit mixture, evenly. Next drizzle the melted butter/maragrine over the top of the dry mix. Bake for approx 35-40 minutes until the top is browned and juices are bubbling out. If you like, you can stick under the broiler to brown it up a little more. Serve warm with vanilla ice cream or room temperature or cold.