The primary ingredient in a chocolate souffle is chocolate, typically dark chocolate, which is melted and mixed with eggs and other ingredients to create a rich, airy texture. Chocolate provides the primary flavor and richness, while the eggs, particularly the egg whites, are whipped to create a light and fluffy structure that allows the souffle to rise beautifully when baked. Sugar is also added to enhance sweetness, and sometimes additional flavors are included such as vanilla or coffee to complement the chocolate.