Jiānbing (煎饼) is the Chinese street crepe folded around egg, sauce, herbs, and something crisp, a thin batter cooked to order on a flat round griddle and built up in seconds while it sets. The angle is contrast managed at speed. Everything happens on one hot disc in under a minute: the batter is spread thin, an egg is cracked straight onto it and smeared flat, sauces go on, a brittle cracker or fried dough stick is laid in for crunch, scallions and herbs are scattered, and the whole sheet is folded into a hot parcel. Get the sequence and the timing right and you bite through a tender, slightly chewy wrap into a loud, shattering core carried on savory-sweet sauce. Get it wrong and the crepe is either gummy and underset or dried hard, the cracker has gone soft, or the sauce drowns the rest.
The build is a fast, ordered routine and the order is the craft. A ladle of thin batter is poured onto the hot griddle and swept into a wide, even circle with a wooden spreader so it cooks thin and uniform with no thick raw patch. An egg is broken onto the still-wet surface and spread across it so it bonds into the crepe rather than sitting on top. The disc is loosened, often flipped, and brushed with a fermented bean or sweet flour sauce and a chili sauce, then scattered with chopped scallion and sometimes cilantro or pickled vegetable. The crisp element, a thin deep-fried cracker or a length of yóutiáo, the oil stick, is set across the middle, and the crepe is folded in from the sides and ends into a hand-sized rectangle, sometimes cut once. Good execution shows in a crepe that is set through but still pliable, an egg fully bonded into it, a crisp center that is still audibly crisp at the first bite, and sauce judged so it seasons without sogging. Sloppy work is obvious: batter spread too thick or pulled too early so the center is gummy, a cracker fried ahead and gone limp, sauce laid on so heavily the wrap slides apart, or a crepe left so long it cracks dry when folded.
It shifts mostly by what crisp goes inside, how many eggs, and which regional sauce profile is used. The Tianjin-style build is the codified reference point, and double-egg, extra-cracker, ham-added, black-sesame, and heavier-chili versions are each defined by a single deliberate change to that base. The thin crispy cracker, báocuì, is its own component with its own article, as is the yóutiáo that some vendors use in its place. Those named variants each turn on one swap and deserve their own treatment rather than being crowded in here, while this entry stays on the core move: a thin crepe built fast around egg, sauce, herb, and a crisp center, folded hot.