Caponata is a traditional Italian dish that is perfect for a vegetarian dinner. It is a sweet and sour eggplant relish that is made by sautéing eggplant, onions, celery, and capers in olive oil, then simmering them in a mixture of vinegar, sugar, and tomato sauce. The result is a flavorful and tangy relish that can be served as a side dish or spread on crusty bread for a light meal.