From cookingwith grazia.com. Note, this authentic Florence recipe says the dried beans should not be soaked overnight, but should be cooked slowly. I did soak my beans overnight to speed the process a bit. This soup is a 2 day event though for it to be at optimum flavor. Recipe serves 6. I would double it and freeze a bunch of it.
½ pound dried cannellini beans (1 1/3 cups)
1/3 cup extra-virgin olive oil
½ onion diced
1 carrot, diced
1 celery stalk, diced
1 garlic clove, minced
2-3 thyme sprigs (leaves only)
1 teaspoon salt
1 potato, medium sized, diced
½ pound lacinato kale (roughly a bunch), sliced
½ head Savoy cabbage (about ¾ lb.), sliced
1/3 pound Swiss chard. sliced
1 Tablespoon tomato paste or 1/3 cup of canned diced tomatoes or 1 fresh tomato
½ lb. whole wheat, rustic, stale bread (brown paesano or pain de champagne or country brown, but a rustic white such as sourdough would also work), cubed
To taste, freshly ground black pepper
Place the (unsoaked!) dried beans in a pot with 4 cups of cold water and just ½ teaspoon of salt. Turn on the heat to medium and bring to a gentle boil, then turn down the heat to the lowest setting and cover with a lid. Keep simmering until cooked (between 3- and 3 ½ hours in my experience). Otherwise use soaked beans and cook them in the same amount of water, until done (cooking time will be quicker). Again, do not use canned beans!!!
Meanwhile, chop the carrot, onion, and celery. Mince the garlic. Peel and dice the potatoes, clean and cut the greens into ½-inch slices. Set aside.
When the beans are cooked, drain them, reserving the cooking water. In a blender or food processor, puree about ¾ of the beans and return the bean purée to the cooking water. Set aside. Also set aside the remaining whole beans.
In a large pot, prepare the soffritto: heat 1/3 cup extra-virgin olive oil, and sauté the carrot, celery, garlic and onion over medium-high heat, until golden in color, about 7-8 minutes. Stir often to avoid burning.
Add the thyme leaves, the remaining 1/2 teaspoon. of salt the remaining fresh vegetables, the tomato paste, the bean purée with its water, along with an additional 4 cups of water. Cook over low heat, covered, for about 1 hour.
Finally, add the previously cooked whole beans and the stale bread, cut into ½-inch slices, crust on. Stir, cook for another 5 minutes and turn off the heat.
Let soup sit for at least a few hours, ideally overnight. Then, reheat the soup, boiling for a few minutes at low heat.
Serve sprinkled with freshly ground black pepper and drizzled with a little high-quality extra-virgin olive oil.
This soup is traditionally served without Parmigiano-Reggiano cheese.