1) Put the beans in a large bowl or stockpot. Cover them with water and let them soak overnight at room temperature.
2) Drain the beans and fill a large stockpot with water. Put the beans in the large stockpot and fill it with 2 quarts (2L) of water and 2 tablespoons (30g) of salt. Cook the beans for 1 hour.
3) When they are cooked, remove ¾ of the beans from the stockpot, without discarding the water, and set them aside. Blend the water and the remaining beans in the stockpot with an immersion blender. Then put the reserved beans back into the stockpot.
4) In a pan over medium to high heat, heat 5 tablespoons (75ml) of the olive oil and add the fresh thyme, carrots, onion, garlic, and celery and cook them for about 6-8 minutes, until they turn golden. Then add the potatoes and the tomato paste with 1 cup (240ml) of water to the pan and let the mixture simmer for a few more minutes. Add salt to taste, along with the kale, cabbage, and Swiss chard. Let them wilt in the pan. Add the beans and let them simmer for another hour on low heat, adding a little water, if the mixture becomes too thick.
5) Now add the sliced bread to the soup and give it a stir. Let it cook for a few minutes over medium to low heat. Take it off the heat and let the soup rest as long as possible, preferably overnight, for the best result. Ribollita means “reboiled,” so the day after you’ve made the soup, bring it to a boil for a few minutes and serve it with a touch of extra virgin olive oil and some freshly cracked pepper.