Yak cheese
A semi-hard to hard cheese made from the milk of yaks or yak crossbreeds, as produced in Nepal and Tibet; mild, nutty and fairly rich.
Yak cheese is an aged wheel cheese made from yak milk or the milk of yak-cattle crossbreeds, produced mainly in the highlands of Nepal and Tibet in the manner of European mountain cheeses. It should not be confused with chhurpi, the rock-hard dried cheese meant for chewing, or the fresh, curd-like cheese of the same region. The milk is very high in fat, so the cheese tastes full and buttery, with a nutty, slightly grassy note and a mild sharpness that grows with age. It slices and grates well and melts softly without becoming very stringy. Outside the Himalaya it is hard to find, occasionally through specialist cheese shops or mail order, rarely in Asian grocery stores.
Substitute:
A medium-aged Alpine mountain cheese or Gruyère comes closest in texture, melting behaviour and nutty flavour. It does not capture the particular richness and distinct, slightly animal note of yak milk, so the dish turns out a little leaner and more familiar in taste.