The main ingredient in a traditional soufflé is eggs, specifically egg whites, which are whipped to create a light and airy texture. Soufflés can be either sweet or savory, using a base of egg yolks, along with other ingredients such as cheese, chocolate, or vegetables to enhance flavor. The key to a successful soufflé lies in the incorporation of air into the egg whites, which, when baked, causes the soufflé to rise and become fluffy. Baking at a controlled temperature allows for a delicate, puffy texture, making soufflés a classic dish in French cuisine known for their elegance.