In modern Iran, kashk is a thick whitish liquid similar to whey or sour cream, used in traditional Persian and Kurdish cuisine, like ash reshteh, kashk e badamjan, kale joush. It is available as a liquid or in a dried form, which needs to be soaked and softened before it can be used in cooking. Kashk was traditionally produced from the leftovers of cheese-making (more specifically, the milk used to make it).