Heat olive oil in a large nonreactive saucepan over medium heat. Add the onions, bell peppers and eggplant; saute 2 minutes. Add the garlic, oregano and chili flakes and continue to saute until all is softened. Add the tomatoes and water and bring to a boil over high heat. Reduce heat and simmer 35 to 40 minutes or until vegetables are tender. Add the Parmesan cheese, chopped basil, vinegar and bread cubes. Allow the bread cubes to soak into the soup and thicken the mixture before serving, about 10 minutes.

for about 20 minutes before being rinsed and used so that it tastes less bitter. You may follow this procedure, but I don't think it's necessary for this soup.