1/2 pound dried white Tuscan beans
1 ham hock or prosciutto bone
3/4 cup olive oil
1/2 cup chopped onion
1 medium carrot, chopped
1 medium celery stalk, chopped
1 small bunch kale, shredded
1 unpeeled potato, cut into small chunks
1 small bunch Swiss chard, chopped
1 large tomato or 1 cup canned tomatoes, chopped
1 clove garlic, minced
1 1/2 teaspoons rosemary leaves
1 1/2 teaspoons chopped parsley
1/2 teaspoon thyme leaves
Freshly ground pepper
6 thick slices Italian or French bread, toasted
1/2 cup freshly grated Parmesan cheese
Place beans in large saucepan and add enough cold water to cover. Let stand at room temperature overnight. Drain beans well and return to saucepan.
Add ham hock and enough water to cover generously. Bring to boil over high heat. Reduce heat and simmer until beans are tender, about 1 1/2 hours. Drain, reserving liquid and ham hock.
Transfer half of beans to food processor or blender and puree (or put through strainer). Reserve whole beans. Remove and discard bone from ham hock. Cut meat into small pieces and reserve.
Heat 1/4 cup olive oil in Dutch oven or large saucepan over medium-high heat. Add chopped onion, carrot and celery and saute about 5 minutes. Stir in kale, potato, pureed beans and about 6 cups reserved bean cooking liquid, adding water if necessary to make 6 cups. Bring to simmer over medium heat until all vegetables are tender, about 30 minutes.
Add Swiss chard, tomato, garlic, rosemary, parsley, thyme and reserved ham. Season to taste with salt and pepper. Simmer until chard is tender and flavors are well blended, at least 1 hour, adding more bean cooking liquid or water if soup is too thick.
Stir in reserved whole beans and reserved ham hock. Simmer until heated through, 5 to 10 minutes. Cool. Cover and refrigerate overnight.
Arrange toast in bottom of large oven-proof soup tureen. Sprinkle with Parmesan cheese. Bring soup to boil. Ladle soup over toast. Top with remaining 1/2 cup olive oil. Bake at 375 degrees until bubbling, about 25 to 30 minutes. Serve in individual terra cotta bowls. Makes 6 to 8 servings.
Note: Ribollita means reboiled, so make large amount and simply reheat, or reboil when needed.