Soak 1 pound white beans overnight in cold water to cover. Drain and put the beans in a soup kettle with a ham bone that still has some meat on it. Add 3 quarts of water. Bring the water to a boil and simmer for about 2 hours. Stir in 1 cup cooked mashed potatoes. Add 3 onions, 1 small bunch of celery, including tops, and 2 cloves of garlic, all finely chopped, and 1/4 cup chopped parsley. Simmer the soup for 1 hour longer, until the beans are thoroughly cooked. Remove the ham bone, dice the meat on it, and return the meat to the soup.
(Bob, a former captain in the Air Force, likes to cook with a patriotic flair. This hearty soup is served in the U.S. Senate every day.)