Sāmǔsà (烤包子/萨姆萨) is the baked meat parcel of China's northwest, a Uyghur relative of the samosa: lamb and onion sealed in dough and baked hard against the wall of a clay oven. The angle is fat and heat. The filling is deliberately fatty lamb cut by a heavy load of raw onion, and the whole point is that the parcel bakes long enough for the fat to render and the onion to sweeten into the meat while the dough crisps around it. Get it right and you tear into a shatter-crisp shell over juicy, oniony, cumin-scented lamb. Get it wrong and it is either a dry meat knot or a soggy fat-logged pocket.
The build is enclosed and corner-folded. A simple wheat dough, sometimes layered with a little fat so it bakes in flakes, is rolled and cut into squares; a spoon of hand-diced fatty lamb mixed with plenty of chopped onion, cumin, salt and pepper goes in the center; the corners are folded to the middle and pinched into a sealed square or triangle parcel. The bottoms are slicked and the parcels slapped onto the inner wall of a hot tandoor-style clay oven, where they grip and bake until the dough colors and crisps and the interior renders to juice. The onion is structural, not a garnish: it gives off moisture as it cooks so the lamb stays moist and gains sweetness. Done well the sāmǔsà comes out with a hard, blistered, golden crust, a thin tender layer of bread just inside, and a hot pocket of lamb slick with its own rendered fat and sweet softened onion, cumin carrying through. Done poorly the failure modes are specific: lean meat with too little onion bakes into a dry crumbly lump; a badly pinched seam splits and the rendered fat pours out, scorching the oven and leaving the meat dry; an over-thick or under-baked wrapper turns into a doughy shell with a small steamed knot of meat inside.
It shifts by filling and by oven. Lamb is the standard, beef appears, and the spicing stays in a cumin-pepper-onion register rather than the chili-heavy profile of inland China. Some bakers pull the dough thin for a cracker-crisp shell, others keep it sturdier. Cooked on the wall of a true clay oven it gains a blistered char; baked in a conventional oven it is cleaner but less dramatic. The steamed Uyghur dumpling forms, the baked sesame shāobing, and the inland roujiamo are each their own preparation and deserve their own article rather than being folded in here. What holds sāmǔsà together as a category is the baked parcel itself: fatty lamb and raw onion sealed in dough and driven hard by oven heat until the crust shatters and the inside runs.