Soak the beans for at least 12 hours before proceeding with preparation.
Once the beans are softened, drain them and boil them in abundant water and rosemary.
Drain the beans, reserving the cooking water and divide them in half. Keep one part whole, the other part puree them with an immersion blender.
Prepare some vegetable broth to use if needed during cooking.
Finely chop the onion, cut the carrots and celery into very small pieces.
Clean, wash and cut the kale, chard and cabbage into pieces.
Peel and cut the potatoes into small pieces.
Sauté the onion, carrot and celery in a large pot with 3–4 tablespoons of oil for 1 minute
Add the cut potatoes and fresh tied thyme. Let brown for 1 minute.
Add the canned tomatoes, brown for a few seconds. Finally add the kale, chard and cabbage. Bring to a boil, add the bean cooking liquid, cover with a lid and let simmer over low heat for about 2 hours, adding the warm bean cooking liquid or vegetable broth from time to time.
After the indicated time the soup will have taken on a cooked appearance, the pieces of vegetables will have softened. Add the bean puree to the soup and let cook for another 30 minutes.
Add the whole beans, cover with hot broth and let cook over low heat for 30 minutes. Season with salt.
Now take an earthenware pot, if you don’t have one, use a thick-bottomed casserole. Add slices of stale bread on the bottom and add some ladles of soup on top. Repeat the operation, adding a layer of bread and one of soup until filling the pot. Cover and let the Ribollita rest for a minimum of 3 hours up to the next day.
When ready to serve, add a couple of ladles of broth, a drizzle of oil and cook again over low heat for about 15–20 minutes, until warmed through. Add more salt and pepper if needed.
The Ribollita is ready, serve it nice and hot!