REMOVE THE MEAT FROM THE TURKEY CARCASS and reserve. You'll need about 1 pound of meat for dinner. Break up the carcass, wrap it in cheesecloth with bay leaves and peppercorns and set aside. Melt the butter in a large pot, add carrot, celery and onion and cook over medium heat, stirring occasionally, 5 minutes. Stir in the flour, then slowly add the water and broth. Add the carcass, cover and bring to a boil. Remove cover and cook 45 minutes. Remove and discard the carcass. Add potato and cook 10 minutes. Place the turkey and salt in the pot and cook 10 minutes more.
Meanwhile, in a saucepan, combine the vinegar and sugar. Let cook until there is no liquid left and the sugar begins to turn dark golden brown. Immediately add the cranberries. Lower heat, cover and let cook 5 minutes, or until the cranberries compote. Pour into a serving bowl. When it's time for dinner, strain the soup into a tureen. Decorate each soup bowl with a mixture of diced vegetables, potato and turkey. Ladle the soup at the table and pass the cranberry compote and sour cream.