Mix instant pudding and buttermilk and set aside, the longer you let it sit the thicker it becomes. Add the cut-up bananas and the fruit cocktail to the buttermilk pudding mixture. Gently fold thawed Cool Whip into the pudding mixture. Chill in the refrigerator for a half hour and serve as a side salad or as dessert.
Note: I have used banana cream, french vanilla, and even lemon instant puddings and keep coming back to the plain vanilla.