Běijīng Kǎoyā Juǎn (北京烤鸭卷)

The duck arrives whole and burnished, the colour of dark amber, and a cook stands over it at the table with a long knife and a practised calm. In four or five minutes the whole bird is reduced to a heap of slices, somewhere around a hundred and twenty of them, each meant to carry a piece of crackling skin and a sliver of meat. Carving Peking duck is its own trained profession in Beijing, and what the carver is really doing is portioning a banquet into the small flat parcels everyone at the table is about to build by hand.

That parcel is the kaoya juan, and it is assembled, not cooked. You take a bao bing, a pale steamed pancake rolled so thin it goes nearly see-through, lay a couple of slices of duck down the middle, add a baton or two of raw scallion and a strip of cool cucumber, and paint the lot with a dark, sweet wheat sauce using a scallion brush or the tip of a chopstick. Then you fold the bottom up and the sides over into a small open cylinder and eat it in two or three bites.

The thing balances on contrasts the assembly is built to hit at once. The pancake is soft and faintly steamy and tastes of almost nothing on purpose, a neutral wrapper whose only job is to hold. The duck skin is the opposite, brittle and shatteringly crisp and slicked with rendered fat. The sweet sauce supplies depth and salt, the scallion a raw allium burn, the cucumber a cold, watery snap to cut the richness. Take any one element away and the bite tilts: no sauce and it eats bland, no cucumber and the fat has nothing to push against.

The build punishes carelessness in small ways. Overfill the pancake and the seam will not close, so the sauce runs out the bottom and the whole thing collapses in your fingers; underfill it and you taste mostly pancake. Brush on too much sauce and it drowns the skin's crispness in sweetness; too little and the duck eats dry. The skin itself is the fragile prize, taken in the pure-skin slices the carver lifts first from the breast, and it goes soft and disappointing the moment it sits too long under sauce or steam.

Eaten in a Beijing duck house, the rhythm is unhurried and communal. The carver works at the table; the diners each roll their own, arguing mildly over the best slices, the crispest skin going fast. It is a dish you assemble with your hands at a shared table rather than receive finished on a plate, which is part of why it has stayed festive: the duck is the occasion, and the wrapping is the part everyone joins in.

The variations are mostly about what the wrap is made of and what stands in for the duck. Some houses serve a thin flour pancake, others swap in small steamed lotus-leaf buns to fold the duck into instead. Sugar and garlic appear as alternate dips for the skin alongside the sweet sauce. What is a different dish, not a version, is the cheap duck-and-pancake wrap sold at a street counter using lesser roast duck; it borrows the structure, a pancake folded around meat and sauce, but not the lacquered, oven-roasted bird that gives the real thing its name.

A Court Roast Carried Out of the Palace

The duck is far older than the restaurants that made it famous, and the paper trail starts in a palace kitchen. A roast duck dish appears under the name shao yazi in a court dietary manual compiled in 1330 by Hu Sihui, an inspector of the imperial kitchen, and the roast the modern dish descends from was fully developed in the later Ming dynasty, by which point it sat among the main dishes on the imperial court's menus. The wrap, as opposed to the roast, is credited by tradition to the table service: a Shandong-born imperial chef is said to have refined the practice of folding the carved duck with scallion, cucumber, and sweet sauce into thin pancakes during the 18th-century reign of the Qianlong Emperor.

The two houses that define the duck split on technique and on time. Quanjude opened in 1864 and built its name on the hung-oven method, the ducks suspended over a fruitwood fire so the skin lacquers and crisps in the direct heat. Older still is the duck's first dedicated house, which roasts in a closed oven, the heat banked and the bird cooked by the chamber rather than open flame. The oven that began turning an imperial delicacy into a thing the whole of Beijing could one day line up for belongs to Bianyifang, established near the Qianmen gate in 1416.