Sopa de cação: Alentejo dogfish soup

The dogfish soup of the Alentejo coast and Setúbal region — a simple, direct preparation of sliced dogfish (cação, a small shark species) in a broth of water, garlic, coriander, vinegar, and olive oil, poured hot over slices of old bread in the bowl. This is açorda principle applied to fish: the bread absorbs the flavoured broth, the fish provides protein, and the vinegar and coriander provide the sharp, herbal complexity. The cação has a firm, slightly sweet flesh that holds up in the hot broth without falling apart. The vinegar in the broth prevents the fish from smelling 'fishy' — this is both a flavour choice and a practical technique from the era before reliable refrigeration.