First take 3 heaping tbl of crushed pinapple and put aside in a strainer to drain. Drain cherries. Take remaining pineapple and juice and pour into a saucepan, add sugar and cook on medium heat until liquid cooks down. Mix cake mix as directed. Add 3 tbl of cake batter to pineapple and cook until thickened. Set aside pinapple filling to cool. Pour cake batter equally into 3 cake pans and cook to make 3 layers. When cooked set aside to cool.