The primary ingredient in a traditional French ratatouille is eggplant, also known as aubergine. Ratatouille is a rustic vegetable stew from the Provence region in France that typically includes a variety of seasonal vegetables. Along with eggplant, other key ingredients often found in ratatouille are zucchini, bell peppers, tomatoes, onions, and garlic, all seasoned with herbs like thyme and basil. The vegetables are usually sautéed or roasted, allowing their flavors to meld together. Ratatouille is both a side dish and a main course, often served with crusty bread, rice, or pasta, showcasing the essence of Mediterranean cooking.