Pickled Mustard Greens

Mustard greens, called qing cai in Mandarin or gai choy in Cantonese, are most often sun-dried, rubbed with salt, and pickled in spices and sugar, as in this Guizhou recipe. Large, fleshy and bright jade, the greens have a crisp and slightly bitter edge when stir-fried, but when pickled they have a robust flavour and texture. They can be left to mature for months in earthenware or ceramic crocks, and are then known as ya cai in Mandarin.