Aquacotta is usually a peasant dish. It's a soup made with stale bread, water, onions, tomatoes, and olive oil. But it's also made in grander households. There, it usually contains eggs, Parmesan cheese, and lemon juice. The version that Marcella lists in her book is of the grander type, and comes from Villa Cappezzana.
I have to say, I was really getting tired of soup and wasn't that excited about making it. But I was really surprised-I loved the soup. You begin by soaking cannellini beans overnight, then cooking them the next day until they're tender. You then make a soup of onions, celery, cabbage, kale, tomatoes, and basil. This mixture cooks for 2-3 hours. I followed all directions except for one-I couldn't find Savoy cabbage anywhere, and had to use regular green cabbage.
When you're ready to assemble the dish, you toast day-old Tuscan-style bread, and layer it on the bottom of a casserole dish. You then top that with the soup and grated Parmesan cheese. You then poach eggs until the whites are just set, and place them on top of the soup mixture. You top with more Parmesan, and place in a hot oven for 10 minutes. You then have this delightful, filling, soup. The flavor of the celery really comes through in this soup, and the poached egg on top really adds the finishing touch.