Ratatouille is a Provençal vegetable stew from Nice that transforms eggplant, zucchini, bell peppers, and tomatoes into a deeply flavorful, silky dish through slow cooking and careful layering. The vegetables release their moisture and concentrate their flavors, creating a naturally rich sauce without cream or stock. It's equally at home as a warm side dish, a room-temperature appetizer, or served cold the next day—making it one of the most versatile and rewarding vegetable dishes in French cuisine.