A true ribollita, which is thick, hearty, and stew-like, is often made several days in advance. A number of leftover ingredients are added to the soup: various meats, such as pancetta, ham, salami, or other similar meats; vegetables and/or greens, such as spinach, kale, cabbage, and zucchini; and beans, such as cannellini. When the soup is ready to serve, it is ladled over slices of crusty bread. Some recipes call for the bread to be toasted, rubbed with garlic and splashed with olive oil, or topped with cheese and broiled.
Some versions of ribollita are prepared fresh; that is, they are not made in advanced but are prepared and served on the same day. In these cases, the soup is removed from the heat and allowed to stand for a time to blend the flavors; then it is re-boiled before it is served.