Yángròu Jiāmó (羊肉夹馍) is the lamb roujiamo, braised lamb chopped and packed into a split baked wheat mó, a common halal build in Xi'an's Muslim Quarter, the Huimin Jie. The angle is the marriage of two separately complete components, with the meat side swung from pork to a spiced lamb that brings its own gamey depth and a heavier cumin signature. The bread is crisp outside and soft and layered inside; the lamb is slow-cooked until it shreds and carries a fragrant, slightly numbing spice. Neither is a garnish for the other. The sandwich works when both arrive at full strength and the braising juice ties them together, and it fails when one is treated as filler.
The build is split-and-pack, not wrap. The mó is a low-leavened wheat disc, often coiled or folded so it bakes in thin sheets, started on a griddle to color both faces and finished in a hot oven so the shell dries to a clean crisp while the center stays tender. It is split most of the way through at the seam ring on its side, leaving a hinge. The lamb, typically shoulder and some fattier cuts, is braised low in a dark stock built on star anise, cinnamon, Sichuan pepper, cumin, and chili until it pulls apart under a knife; it is then chopped on a board, fat and lean together, and pressed warm into the bun with a spoon of the braising liquid, often with chopped fresh chili or coriander worked in to lift the richness. Done well it shows a shell that gives a quiet crack, an interior that pulls in soft layers and soaks a little juice without going to paste, and lamb that is tender, glossy, and deeply spiced with the gamey edge balanced rather than buried. Done poorly the failure modes are plain: an under-baked bun turns to gum around the hot meat, an over-baked one is a hard biscuit that fights it, lean-only or rushed lamb is dry and muttony, and too much liquid blows the bottom out before the second bite.
It shifts mostly by the spice load and the fat of the lamb. A heavily cumin-and-chili braise reads northwestern and aromatic; a milder, more aniseed-forward stock keeps the lamb's own flavor forward. Fattier cuts in the braise stay juicier and more luxurious in the bun, while lean-heavy versions need more liquid to carry. The pork roujiamo, the donkey-meat regional line in its own bread, the split mó as a craft of its own, and the standardized chain format are each a distinct preparation that deserves its own article rather than being folded in here. What holds yángròu jiāmó together as a category is the pairing itself: a crisp layered bun, a long spiced lamb braise, and the cumin-scented juice between them.