Cháyèdàn + Mántou (茶叶蛋+馒头) is a plain steamed bun eaten with a tea-marbled egg: a minimal breakfast pairing rather than a constructed sandwich. The angle is contrast through restraint. A mántou is unsweetened or barely sweetened steamed wheat bread with no filling, soft and faintly chewy and deliberately neutral. A cháyèdàn is a hard-cooked egg whose shell is cracked and then simmered in a brew of tea, soy, and spices until the white takes on a marbled brown pattern and a savory, faintly bitter, five-spice flavor. Put together they work because each supplies what the other lacks: the bun is bland and dry, the egg is salty, aromatic, and moist.
The build is two separate preparations brought to the same plate. The mántou is a yeasted wheat dough, kneaded and proofed, shaped into a smooth dome or roll and steamed until soft and glossy with a tender, slightly springy crumb. The cháyèdàn starts from hard-boiled eggs whose shells are gently cracked all over, then returned to a simmering bath of black tea, soy sauce, star anise, cinnamon, and often dried orange peel or fennel, and held there long enough for the marinade to seep through the cracks and color and season the white. Good execution shows in both halves at once: a bun that is soft, not gummy or collapsed, with a clean wheat taste, and an egg that is fully marbled, seasoned through the white rather than only on the surface, with a yolk that is set but not chalky. Sloppy versions are easy to read. A mántou that was oversteamed turns wet and wrinkled, and an underproofed one is dense and tight. An egg simmered too briefly is pale and bland inside the shell with only a thin brown skin, while one boiled too hard has a grey, dry yolk that crumbles. Eaten together, an overly salty egg can swamp the gentle bun, and a stale bun makes the egg seem the only thing worth eating.
It shifts mostly by the egg's seasoning and how the two are eaten together. A lighter tea brew gives a milder, more delicately spiced egg; a long, dark soy-heavy steep gives a deeply savory one that dominates. The bun can be torn and used to scoop softened egg, or the egg eaten in bites between mouthfuls of plain bread, the rhythm changing how strong each tastes. Filled steamed buns and the fried, savory street breads are separate preparations that work on different principles and deserve their own articles rather than being grouped in here. As a breakfast it is usually part of a larger plain spread with soy milk or congee, the egg providing the salt and aroma against several mild starches.