Zájī Jiānbing (杂粮煎饼) is the mixed-grain reading of the street crepe: the same fold-around-egg-and-crunch routine as a standard jiānbing, but with a batter cut from several grains rather than mung bean alone, so the wrap eats nuttier and with more body. The angle is the grain note. Swapping in millet, corn, sorghum, or other coarse flours changes the crepe from a near-neutral tender sheet into something with a faintly toasted, cereal flavor that has to carry through the sauce and filling instead of being buried by them.
The build is the familiar fast routine and the order is the craft. A thin batter of blended grain flours is ladled onto a hot flat griddle and swept into a wide even round with a wooden spreader so it cooks uniform and thin; an egg is cracked straight onto the wet surface and smeared flat so it bonds into the crepe. The disc is loosened and often flipped, brushed with a fermented bean or sweet flour sauce and a chili sauce, then scattered with chopped scallion and sometimes herb or pickle. A crisp element, a thin fried cracker or a length of yóutiáo, is laid across the middle, and the crepe is folded in from the sides and ends into a hand-held parcel, sometimes cut once. Done well the zájī jiānbing keeps the grain flavor forward under the sauce, sets through while staying pliable, holds an egg fully bonded into it, and stays audibly crisp at the center. Done poorly the failure modes are specific: the multi-grain batter spread too thick or pulled too early stays gummy and raw; over-baked it goes brittle and cracks when folded because coarse flour has less stretch; too much sauce sogs the wrap and the crisp insert goes limp; a bland grain mix and heavy sauce together flatten the nutty note the whole version exists for.
It shifts by which grains dominate and by what crunch and filling go in. A millet-heavy batter runs softer and slightly sweet; a corn or sorghum lean runs coarser and more robust; the crisp insert ranges from a brittle cracker to a fried dough stick, and added ham, extra egg, or heavier chili each define a one-change variant. The thinner Tianjin mung-bean jiānbing, the thick chewy Shandong grain crepe, the standalone báocuì cracker, and the yóutiáo itself are each their own preparation and deserve their own article rather than being crowded in here. What holds zájī jiānbing together is the batter: a mixed-cereal crepe built fast around egg, sauce, herb, and a crisp center, folded hot with the grain kept tasteable.