Chao Tom

Nothing structural. An assertive sauce is the safest home for a bag that may read iodine-y, and dry heat concentrates rather than dilutes - but whether any method actually masks or exposes bromophenols has never been measured, so this is a hedge and must be labelled as one.

Treat it as Group A for every cooked method, and as a raw ingredient only when it arrives alive or air-freighted whole. Its classical cooked preparation, irojime, is worth teaching on its own: live prawns skewered head to tail to stop them curling, dropped into heavily salted water with a splash of vinegar, then shocked in ice.

Rank it first for grill and pan sear. It wins on three measured counts: largest commercial shrimp so the longest browning budget; narrower myofibrillar spacing and lower T2 relaxation so it holds water more tightly and puts less exudate in the way; and higher astaxanthin for a deeper cooked colour.

Grill, sear or roast it, one to two minutes a side, pulled early because it carries over. Peel it raw, which is easier than peeling it cooked. Boil-and-drain stays ruled out: a boil flushes the hepatopancreatic fat that California Sea Grant says dry heat exists to keep.

Grill it. It is the best griller in the whole table on size alone, at about six head-on animals to the pound. The one precondition is R8, and it is sharper here than for any other species: the extension literature states explicitly that freshwater prawns are MORE susceptible to head-enzyme breakdown than marine shrimp, so it must have been deheaded promptly.