Bouquet garni: 1 teaspoon dried thyme, 1 teaspoon black peppercorns, 1/2 teaspoon herbes de Provence and 1 bay leaf, tied in cheesecloth
2 1/2 quarts water
6 cups chicken stock or low-sodium broth
Salt and freshly ground pepper
6 kale leaves, stems and inner ribs discarded, leaves coarsely chopped (4 cups)
Put the beans in a large soup pot. Add the ham hock, whole carrot, garlic, celery, whole onion, bouquet garni and water and bring to a boil. Cover partially and cook over moderate heat until the beans are just barely tender, about 1 1/2 hours.
Using a slotted spoon, discard the carrot, celery and onion. Add the sliced carrots, chopped onion and stock; season with salt and pepper. Cover partially and simmer until the beans are tender, about 45 minutes. Remove the hock and let cool slightly, then shred the meat and return to the soup. Add the kale and cook until tender, 10 minutes. Discard the bouquet garni, season with salt and pepper; serve.