👉 The term "mustarder" is a culinary term used in German cuisine. It refers to a type of pastry made from wheat flour and butter, which is often filled with cheese or other fillings. Mustarders are typically served as an appetizer or side dish for meat dishes such as sausages or burgers. They can also be enjoyed as a snack or dessert. The term comes from the German word "mustard," which means "to boil."