Pastry fillings are mixtures used to enhance the flavor and texture of pastries. Common types include sweet fillings like chocolate, fruit preserves, and custard, as well as savory options such as cheese, meat, and vegetables. These fillings can be used in various pastries, including tarts, pies, and croissants. The choice of filling often depends on the type of pastry and the desired taste. For example, apple pie typically features a sweet apple filling, while quiches are filled with a savory mixture of eggs, cream, and vegetables. The right filling can elevate a pastry, making it more enjoyable.