How to Make It
In a large pot, combine the smoked ham hocks with the cannellini beans and water and bring to a boil. Cover and simmer over low heat for 1 hour. Add the potatoes, leek, celery, carrot, parsnip, cabbage and 1/2 teaspoon of salt. Cover the stew and simmer over low heat for 1 hour.
Transfer the ham hocks to a plate. Simmer the stew uncovered over moderate heat until thickened and the beans and vegetables are very tender, about 45 minutes.
Meanwhile, discard the skin and bones from the hocks and cut the meat into bite-size pieces. Add the meat to the stew as it simmers. Season the stew with pepper.
Preheat the broiler. Ladle the hot stew into 8 heatproof soup bowls and place the bowls on a large cookie sheet. Cover each bowl with a toast and spread the cheese on top. Broil 4 inches from the heat, rotating the bowls as necessary, until the cheese is lightly browned, about 3 minutes. Serve right away.