Preheat oven to 350 degrees F. Melt 6 tablespoons butter in 9 x 13 pan in oven. Remove pan from oven and sprinkle bottom with brown sugar. Decoratively arrange pineapple slices. Fill in spaces with cherries. In a bowl, combine cake mix, eggs, oil and crushed pineapple. Mix for 2 minutes. Pour over pineapple slices. Bake for 40 minutes or until done. Remove from oven. Very carefully invert onto serving platter. Serve warm or room temperature topped with whipped cream.