Vicenza, Veneto — the Confraternita del Baccalà alla Vicentina has maintained the recipe and the technique since 1987, but the preparation is documented from the 15th century, when stockfish from Norway arrived in Venice via the Hanseatic League trade routes.
Baccalà alla Vicentina is one of the great fish preparations of northern Italy, made from stockfish (stoccafisso — air-dried, unsalted cod) rather than salt cod, soaked for 3-4 days until softened, then braised for 4-6 hours in a mixture of milk, anchovies, onion, and olive oil over the lowest possible heat until the fish has dissolved almost completely into the sauce, and the sauce has taken on a creamy, intensely savoury character. Despite its name (baccalà), the Vicenza preparation always uses stockfish — the confusion between baccalà (salt cod) and stoccafisso (stockfish) is specific to the Veneto dialect.
Baccalà alla Vicentina is ivory-white, creamy, and intensely savoury — the dissolved anchovies and the fish gelatin create a sauce of remarkable depth, punctuated by the sweet, delicate flavour of the rehydrated stockfish. On yellow polenta, it is the paradigm of Venetian cooking: maritime flavour brought inland, transformed by patience and very gentle heat.
Soak the stockfish in cold water for 3-4 days, changing water daily, until fully rehydrated and no longer stiff. Remove all bones and skin. Place in a heavy, wide pot: a layer of thinly sliced onion softened in olive oil, then the stockfish pieces, then more onion, then anchovy fillets (5-6 salted anchovies, desalted), grated Parmigiano, salt, pepper, and enough milk to almost cover. Cover tightly and cook over the absolute minimum heat (a diffuser is useful — the pot should barely tremble) for 4.5-5 hours without stirring — the fish should be moving gently, not boiling. The result should be a creamy, ivory-white sauce with the fish dissolved into it.
The heat diffuser is critical for achieving the barely-trembling simmer — without it, domestic burners are typically too hot at their minimum setting. A cast-iron pot on the lowest gas with a diffuser achieves the correct result. The olive oil in the final product forms an emulsion with the milk proteins and fish gelatin — the sauce should be creamy and coating, not oily.
Boiling rather than barely simmering — vigorous heat makes the fish dry and makes the milk curdle. Using salt cod (baccalà) instead of stockfish — the flavour and texture are completely different. Stirring during cooking — the fish should remain intact until the very end; stirring breaks it up prematurely. Insufficient cooking time — 4 hours is the minimum; underdone baccalà alla Vicentina has a fibrous, unpleasant texture.
Marcella Hazan, Essentials of Classic Italian Cooking; Giorgio Locatelli, Made in Italy