Yogurt, Dried Buttermilk

In the West, whey means the thin liquid separated from milk curds during cheesemaking. The term is often used to refer to the Persian kashk, however, in Iran, kashk refers to dried, salted buttermilk (soured skimmed milk), and is used as a high protein, low fat souring agent in many dishes. Kashk is sold in both solid and liquid form at Iranian groceries in the U.S. You may substitute sour cream, but if you do, you will not get the distinctive, slightly sour taste or the low fat qualities of kashk.