Ash reshteh is a classical Iranian dish that is often made for New Year’s celebrations or served during cold winter nights. It is a thick, filling soup made from a variety of beans, spinach or beet greens, and pasta. The ingredients are combined and cooked together in a pot with water or stock until the liquid has reduced down to a heavy, stew-like consistency. Just before the dish is completed, kashk is added to provide a creamy texture. When served, the soup is often decorated with designs made from kashk floating on the surface, as well as fried onions, fried mint and, sometimes, fried minced beef.
One of the basic ingredients in ash reshteh is beans. The recipe usually calls for a combination of navy beans, kidney beans, chickpeas and lentils. Lentils cook much more quickly than other types of beans and are usually added after the others have started to cook. The beans need to be soaked overnight if they are dried to ensure they are soft, although canned beans also can be used.
Another important element in the dish is the pasta. In Farsi, "reshteh" is the word for "pasta". The exact type of pasta that the traditional recipe calls for is unclear, because reshteh generally refers to all pasta, but it has come to refer mainly to thin noodles, not unlike Italian angel hair pasta. The reshteh is usually broken into pieces when it is added to the dish, partly to make it more edible and partly because of a tradition that it is good luck for future travels.
Ash reshteh is prepared by first frying onions and garlic in oil in a pan. Once completed, water or stock is added to the pan and taken to a boil. Flour is added to the boiling liquid to help thicken the sauce; the reshteh and any spices — such as mint, parsley and cilantro — also are added. Everything is allowed to cook until the pasta is done.
The beans are then added to the ash reshteh, along with more liquid, if needed. The entire mixture is allowed to cook until the beans are soft and the liquid in the pot has reduced and become thick. The actual thickness of the final soup is left to the discretion of the cook but can range from very liquid to almost paste-like. Right at the end before cooking has finished, kashk, a type of whey resembling sour cream, is added.
The finished ash reshteh is poured into a bowl and any number of designs can be made on the top with additional kashk. Fried mint can be sprinkled over top, as can fried crispy onions or minced beef and garlic. Some recipes call for ash reshteh to be made a day in advance and kept overnight so the flavors have time to age and develop, although this is not necessary.