water chestnuts
The crunchy corm (an underground stem, not a nut despite the name) of an aquatic plant, sold sliced in cans, with a mild, faintly sweet flavor and a crisp texture that stays crunchy even after cooking -- used in stir-fries and Asian-style soups mainly for that texture contrast rather than for flavor.
Buying guidance
Sold canned, sliced or whole, in the Asian foods aisle -- canned is by far the most common form outside a specialty market, since fresh water chestnuts need peeling and aren't widely stocked.
Substitutions
- Jicama, diced -- a similar crisp, mildly sweet crunch.
- Celery -- crunchy but with its own distinct flavor, a reasonable textural stand-in.
- Omit entirely -- the dish loses a bit of textural contrast but is otherwise complete.
Tips & common mistakes
Overcooking them defeats their whole purpose -- unlike most vegetables, they're added for crunch, so they should go in late enough to just heat through rather than simmer for a long time.
Storage
An unopened can keeps for a year or more in the pantry. Once opened, refrigerate any unused portion covered in water (changed daily) and use within about a week.