mitsuba
Japanese wild parsley with three-part leaves and long, tender stems, fresh and slightly bitter, somewhere between parsley, celery and angelica.
Mitsuba is a member of the carrot family whose leaves are divided into three leaflets, hence the name, which means “three leaves”. Both the leaves and the fine, pale stems are used; they have a clear, cool aroma reminiscent of parsley and celery leaf, with a slightly resinous, bitter edge. The aroma is volatile and fades with longer cooking, so mitsuba is usually added at the very end to broths, savoury egg custards or rice dishes, or used raw as a garnish. Fresh bunches turn up occasionally in well-stocked Asian grocers or Japanese food shops, often only seasonally. Growing it yourself is more reliable: seeds are available from mail-order seed suppliers, and the plant does well even in partial shade on a balcony.
Substitute:
Flat-leaf parsley with a little celery leaf comes closest in flavour, but tastes coarser and grassier; the cool, slightly resinous note and the tender stems are missing. There is no true equivalent, so use it sparingly so the parsley does not dominate.