Tofu, dried-frozen (koyadofu)

Koyadofu, or dried-frozen tofu, is a traditional Japanese ingredient made by freezing tofu and then slowly dehydrating it, which gives it a spongy, porous texture very different from fresh tofu. Before cooking it is rehydrated in warm water until it softens and expands, then simmered in a seasoned dashi broth so it soaks up the surrounding flavors, a technique central to Japanese home cooking and traditional shojin (Buddhist temple) cuisine. Its firm, chewy bite holds up well in simmered dishes, nabemono hot pots, and vegetable stews where fresh tofu would fall apart.

Because it is dried, koyadofu keeps for a long time unopened in a cool, dry pantry and only needs refrigeration once rehydrated and any leftovers are stored. A single small piece (17 g) delivers 477 calories per 100 g equivalent, with 52.5 g of protein per 100 g, 105 percent of the Daily Value, plus 54 percent of the Daily Value for iron and 28 percent for calcium, making it an unusually concentrated plant source of these nutrients for its size. Its low sodium at 6 mg per 100 g means the seasoned broth it is simmered in does most of the flavoring work.