I think I could write a book about caponata. I realize that this is a rather dramatic statement to make about something as simple as onions, celery, zucchini and eggplant cooked with tomatoes. But it’s the vinegar combined with just a touch of sweetness (in my case always honey) that makes this Italian version of the French ratatouille a subject of endless possibilities. Like each day of the week — caponata is never the same way twice — and this is exactly why I love it.