Guan Shao Flatfish

"Mu yu" here means flatfish — flounder or sole, a fish the Bohai Gulf yields in plenty — not cuttlefish, for which the same characters are sometimes used elsewhere. The dish belongs to Tianjin's sweet-and-sour seafood repertoire, a style the city's restaurants refined from the older Shandong (Lu) cooking that shaped much of northern banquet cuisine. The "guan," official, in the name is popularly explained by a legend: that the Qianlong emperor, passing through Tianjin, tasted the dish, praised it, and that the cook who made it held some petty official post — so it came to be called the "official's braised flatfish." The story is folklore, told as a flavor of the dish rather than as fact; its documented history is simply as a long-standing house specialty of the city's seafood kitchens.

The fish comes in glossy, sauce-slicked strips that catch the light orange-red. Bite through a crust still faintly crisp at the edges and you reach soft, white flesh that flakes clean and sweet — flounder is delicate, and the quick fry keeps it from drying. The sauce hits sweet first, then a clean vinegar tartness right behind, all over a savory base, with slivers of mushroom and bamboo shoot adding their own gentle chew. It is lively and appetite-whetting, the kind of bright sweet-sour plate that wakes up a banquet table.

The technique is a deep-fry followed by a glaze-toss, much like the city's other sweet-sour fish. Skinned, boned flatfish is cut into even strips and coated in a starch batter, then fried — often twice — so a firm shell forms that will survive the saucing without going limp; flounder's tender, water-rich flesh would fall apart braised, so the fry both cooks it and armors it. Separately a sweet-and-sour sauce is built — sugar and vinegar in balance, soy for color and savor, a little stock — and thickened with starch into a clear, clinging glaze (the gou qian that gives the dish its shine). The fried strips and the shredded mushroom, bamboo and ginger are folded into the hot sauce off the main heat and tossed only briefly, so the crust drinks the glaze but does not soften. Toss too long and the shell collapses; that is the usual fault.