In the Champaran district of north-west Bihar, near the Nepal border, mutton is cooked in an ahuna or handi: a clay pot packed with raw meat, whole bulbs of garlic, onions, mustard oil and spices, sealed shut with dough and left for hours on a slow charcoal fire. Nobody adds water and nobody stirs; the meat cooks in its own juices and the garlic turns soft and sweet. Roadside dhabas on the highways out of Motihari made it famous, and it is now cooked at family picnics and parties right across Bihar, eaten with rice or rotis. This home version uses a heavy pot sealed with foil and a lid. Chef's tip: shake the pot instead of opening it; every time the lid comes off, steam escapes and the meat dries out.