In A Large Soup Pot, heat the oil and cook the onions, stirring occasionally, until softened, about 10 minutes. Add the cabbage and continu e to cook, stirring occasionally, about 20 minutes. Add the chicken broth, vinegar and ham hock. Cover and simmer the soup for 1 hour. Remove from heat, add salt and pepper as desired. Remove meat from ham hock and add bac k to soup. Serve with sour cream and chopped fresh dill.