Bacalao al pil-pil is the Basque Country’s dish in the postage-stamp series by the Postal Service with the Royal Academy of Gastronomy, presented in Bilbao. It is a recipe of Basque cuisine in general, without a documented city of origin, linked to the long trade in salted cod in Basque ports.
The name imitates the sound of the oil bubbling in the clay pan while the fish cooks. Cod loins, desalted for one or two days, are placed skin-side up in warm oil already scented with sliced garlic and guindilla chili.
The technique is in the motion. The pan is kept constantly shaking in circles, or the oil is beaten with a strainer, until the gelatin the cod releases from its skin mixes with the oil and forms the pil-pil, a clear, thick sauce. It contains no flour, egg, or milk: the emulsion comes only from the fish.
The dish is brought to the table in the same clay pan in which it was made, with the sauce covering the fish and the garlic golden on top. It is a fixture in taverns and in Basque gastronomic societies, the clubs where members cook together.