Mahlepi has been widely used throughout the Mediterranean for centuries, to flavor breads, biscuits and less sweet cakes and pastries. In Greece mahlepi is used for holiday desserts such as tsoureki and other egg based yeast cakes. It's an unusual and fragrant spice made from the stones of the black cherry tree Prunus mahaleb, which grows throughout the Mediterranean and Middle East.
The cherry stones are cracked and the kernels are extracted, dried, and sold as mahlepi. Before using, the kernels must be ground to a powder either with a mortar and pestle or with a coffee grinder. The flavor of mahlepi is a combination of almond and cherry, and it gives a sweet nutty tone to the desserts it flavors. It can be found in specialty Greek or Middle Eastern stores where it is available both whole or ground. However, as it quickly deteriorates once ground, it is preferable to purchase whole and grind the kernels when needed. Store it in airtight containers. Tip: for a subtle note add one teaspoon of ground mahlepi to pastry for fresh fruit flans. Try adding a bit of mahlepi to rice pudding.