Dissolve gelatin in hot water. Add pineapple and juice from can. Add bananas and sour cream. Place in bowl to chill. Combine in saucepan - pineapple juice, sugar, egg, flour and butter. Cook over low heat; when thick add 1 (3 ounce) package cream cheese. Fold in 1 package whipped topping (prepared). Frost chilled gelatin with the topping. Serves 12.