An ontbijtkoek, peperkoek or kruidkoek is a Dutch and Flemish spiced cake. Rye and dark brown basterdsuiker are its most important ingredient, coloring the cake light brown. It is often spiced with cloves, cinnamon, ginger, succade and nutmeg. Several parts of the Netherlands have their own local recipe, of which the most famous is oudewijvenkoek, which is mostly eaten in the northern regions, and is flavored with aniseed. Ontbijtkoek is traditionally served at breakfast with a thick layer of butter on top, as a replacement for bread, however, due to its sweet taste it is also served as a snack. It is best eaten the day after it is baked, but has a shelf life of several weeks at room temperatures without spoiling due to the pH, sugar content, and spices.