Bolinho de Bacalhau

The dish is Portuguese, built on bacalhau — salt cod, preserved Atlantic cod that Portuguese fishermen worked off Newfoundland from the fifteenth century and which became the protein of the Catholic meatless calendar of Lent and Fridays. It cannot predate the potato, documented in Portugal only in 1760, so it is an 18th-to-19th-century creation rather than a relic of the Age of Discoveries. The earliest recorded cod 'bolinho' appears in Vilarinho de São Romão's cookbook of 1841, though that version resembled a flatter fritter; the modern standardized recipe — shredded cod, cooked potato, parsley and egg, deep-fried — was set down by Carlos Bento da Maia in 1904 and is usually credited with fixing the name 'bolinhos de bacalhau'. Food historians attribute the dish to the Minho region of northern Portugal. It reached Brazil with Portuguese settlers and spread after the royal court moved to Rio in 1808; the first salt-cod shipments from Norway followed in 1843. In Rio the Portuguese pastel — quenelle-shaped, formed with two spoons — became the rounder, airier bolinho of the boteco counter.

A golden ball the size of a small egg, crisp-shelled and audibly crunchy, opening on a pale, fluffy, almost cloud-like interior. The flavour is salty-savoury and umami-deep from the cod, lifted by the green note of parsley, with the potato keeping it light rather than dense. A squeeze of lime brightens it; the ice-cold beer it is always served with cuts the richness. Eaten hot from the fryer, standing at a bar counter or a kiosk on the sand.

Salt cod must first be desalted: soaked in cold water in the fridge, the shredded cod for eight to twelve hours with two or three changes of water, to bring the salt down from around a fifth of its weight to a palatable level. Salting works by osmosis, pulling water out and lowering water activity so spoilage bacteria cannot grow; it also denatures the protein, which is why reconstituted cod stays firm and flaky. The potato must be cooked, riced and dried so its steam escapes — wet potato makes a greasy, heavy bolinho. Whipped egg whites are sometimes folded in for lift. Frying temperature is decisive: too cool and the croquettes soak up oil, too hot and the shell burns before the centre sets.