Drain pineapple chunks, reserving ½ cup of the juice. Place pineapple and banana chunks in a baking dish. Mix juice and preserves in a measuring cup and heat in the microwave until preserves are melted. Pour this mixture over the fruits.
Mix together the topping ingredients and spread over top of casserole. Bake @ 325 or 350 for approximately 30 minutes. (The day before – mix all topping ingredients except for butter and leave out on the counter in a covered bowl for completion in the morning.)