Mix jello into hot water and add marshmellows . Drain crushed pineapple keeping juice for topping and add pineapple to jello mixture. Dice bananas and add to jello mixture. Place in refrigerator and let set. Now make topping. Mix sugar, eggs, pineapple juice flour and butter. Cook until it is like pudding, set aside and cool. When jello set put cooled pudding on top then spread whipped topping over and sprinkle with nuts.