Perhaps your new favorite bean dish:
Soak beans in cold water for 8 hours. Now drain water, boil beans in water until soft (about 2 hours).
An hour before beans are soft, saute onions and celery in a second saucepan until soft. When the onions have turned golden brown, add the peeled and seeded tomatoes. After five minutes, season with salt and add the potatoes. Cook at low temperature, adding a little warm water if necessary, until the potatoes are soft.
In the meantime, the beans are also soft: add them and simmer for five minutes.
Now cut the bread into very thin slices, spread them on the heated soup plates, sprinkle grated pecorino between each layer of bread.
Adjust the right consistency of the soup with hot water, season and pour over the bread. Soak for two to three minutes and bring to the table.