All plant parts of Brown Mustard are used in Nepali cuisine, particularly in the mountain regions of Nepal, as well asin the Punjab cuisine of India and Pakistan, where a dish called sarson da saag (mustard greens) is prepared. B. juncea subsp. tatsai, which has a particularly thick stem, is used to make the Nepali pickle called achar, and the Chinese pickle zha cai.
The Gorkhas of Darjeeling, Sikkim and Nepal prepare pork with mustard greens (also called rayo in Nepali). It is usually eaten with relish and steamed rice, but can also be eaten with roti (griddle breads). In Nepal it is also a common practice to cook these greens with meat of all sorts specially goat meat; which is normally prepared in a pressure cooker with minimal use of spices to focus on the flavour of the greens and dry chillies. Brassica juncea (especially the seeds) is more pungent than greens from the closely related Brassica oleracea (kale, broccoli, and collard greens), and is frequently mixed with these milder greens in a dish of "mixed greens".
Chinese and Japanese cuisines also make use of mustard greens and seeds. In Japanese cuisine,the leaves make a dish known as takana and often pickled for use as filling in onigiri or as a condiment. Many varieties of B. juncea cultivars are used, including zha cai, mizuna, takana (var. integrifolia), juk gai choy, and xuelihong. Asian mustard greens are most often stir-fried or pickled. A Southeast Asian dish called asam gai choy or kiam chai boey is often made with leftovers from a large meal. It involves stewing mustard greens with tamarind, dried chillies and leftover meat on the bone. Brassica juncea is also known as gai choi, siu gai choi, xaio jie cai, baby mustard, Chinese leaf mustard or mostaza.