lotus root
The thickened underwater stem of the lotus plant, run through with air channels that give every slice a flower-like pattern. Crisp, mild and faintly sweet.
Lotus root is in fact the rhizome of the lotus plant, growing in sausage-like linked segments in pond mud and pierced lengthwise by several air channels. It tastes mild, faintly sweet and slightly starchy. What matters most is the texture: briefly cooked it stays crisp like a raw apple, while long braising makes it softer and a little sticky. Once peeled and cut it quickly turns grey, so the slices are kept in water with a splash of vinegar until used. Fresh lotus root is sold in Asian grocery shops, ideally as firm, unblemished pieces with sealed ends, and it is also available precooked in brine in vacuum packs or frozen in slices.
Substitute:
There is no real substitute, since neither the pattern of holes nor the faintly starchy flavour is found elsewhere. Where only the bite matters, canned water chestnuts or jicama give a similar crunch, but they are juicier and sweeter and do not turn sticky with long braising.