Abalone is a large marine snail — a single-shelled gastropod mollusc — whose ear-shaped shell, lined with shimmering mother-of-pearl, clamps to surf-washed rock by an enormous muscular foot. That foot is the prize: a dense, ivory disc of meat, sweet and briny with a deep oceanic umami. Naturally very firm, it is eaten either sliced paper-thin and raw as sashimi or coaxed soft by hours of slow simmering — and, made scarce by overfishing and poaching, it is among the most expensive seafoods in the world.