Imeretian cheese
A young Georgian brined cheese made from cow's milk, soft, slightly crumbly and mildly tangy and salty.
Imeretian cheese is a fresh cow's milk cheese from the western Georgian region of Imereti, set with rennet and matured only briefly in brine. It is white, moist and slightly crumbly yet a little springy, with a mild lactic tang and restrained saltiness. When heated it melts soft and creamy without pulling into long strings, which makes it the classic cheese for khachapuri and many filled breads. Outside Georgia it is most likely found in Georgian, Russian or Eastern European grocery stores, often frozen, or by mail order.
Substitute:
A well-tested mix is roughly two parts mozzarella to one part feta: the mozzarella provides the melt, the feta the salt and tang. The result is stringier and somewhat saltier than the original; for a milder version, replace part of the feta with drained cottage cheese or farmer's cheese.