Shanghai Crab Shell Yellow is Shanghai's long-established specialty snack. It was founded in the early 1920s and is best known for its crab shell yellow cooked by Wu Yuan. The stuffing of crab shell yellow is salty and sweet, salty with onion oil, fresh meat, crab powder, shrimp, etc., sweet sugar, rose, bean paste, jujube and so on. Because the shape of the cake resembles a crab shell, the color after ripening is as deep as the back of the crab shell, so it is called "crab shell yellow".