Báitáng Guōkuī (白糖锅盔) is the white-sugar version of guokui, a thick griddle-baked wheat flatbread carrying a seam of plain sugar that melts as it cooks. The angle is heat and timing rather than richness. There is almost nothing in this guōkuī beyond dough and sugar, so the whole effect rests on getting the inside to a molten sweet pocket while the outside firms to a dry, slightly chewy crust, in a window of a minute or two. Done right you break it open and the sugar runs hot and just shy of caramel; done wrong the sugar stays gritty and undissolved or scorches black against the pan.
The build is a folded-and-flattened bread, not a filled pie. A firm, low-water wheat dough is rested until it rolls out without snapping back, then brushed thin with oil and dusted heavily with white sugar before being rolled up, coiled, and pressed flat so the sugar sits in spiraled layers through the disc rather than in one lump that would burn. The shaped round goes onto a hot dry or barely greased griddle, weighted or pressed so both faces brown evenly, and is turned through until the surface is firm and freckled and the center has gone soft and liquid. Good execution shows a crust that is dry and a touch crisp with a chewy crumb just beneath, and a center where the sugar has fully melted into the dough without pooling out. The failure modes are specific: too much sugar in one place blows out a hole and the syrup welds to the pan and burns bitter, too low a heat leaves the sugar grainy and the bread pale and tough, and skipping the coil step gives you a sweet patch in the middle and dry bread everywhere else.
It shifts by how the sugar is handled and what is added with it. Some cooks fold in a little crushed sesame, walnut, or a pinch of osmanthus with the sugar to push it toward fragrant rather than flatly sweet; a brushing of sesame on the outer face adds aroma and a darker toast. The savory members of the same family swap the sugar for scallion, salt, or spiced minced meat and are pressed and griddled the same way, and those are their own preparations rather than crowded in here. The thick, sturdy build is what holds the line: thin it out and it becomes a different flatbread, but kept dense and griddle-hardened around a melted sweet core it stays squarely báitáng guōkuī.