Melt butter in a 7 qt. or 12" Lodge Dutch oven. Add sugar, then pineapple, placing a cherry in the center of each pineapple slice. Prepare cake mix as directed and pour over pineaple. Bake at 350º for 25 minutes. Let oven cool with top off. To remove cake cut around sides and insert 2 or 3 paper plates covered with aluminum foil and flip.