Pil pil: how the Basques turned salt cod and olive oil into one of the world's great sauces

 The simplest and most demanding sauce in Basque cooking has centuries of history behind it

In his book The Basque History of the World, Mark Kurlansky recounts how, in the 10th century, the Vikings were able to undertake long ocean voyages and cross the Atlantic because they stocked their ships with cod dried in the Arctic air. From those intrepid sailors — who had made their way to the banks of the Adour river in search of whales — the Basques learned shipbuilding techniques and, crucially for our story, improved the cod-drying process by adding salt.
The difference was enormous. Viking dried fish, Kurlansky tells us, "looked like a piece of balsa wood; to prepare it, the cook broke it apart and chopped it with a hammer." The Basque method, by contrast, allowed the fish to be soaked back to life and made edible again. It was a leap forward that changed not just gastronomy but history itself: it was this salted cod that provisioned the Basque whalers on their extraordinary voyages to the American coast — almost certainly before Columbus — with the hold full of salazón and the crew fed for months at sea.

Salt cod, soaked and desalted, ready to make the pil pil

That ancient technique is woven deep into Basque history and into Basque cooking. Salt cod appears in dozens of preparations — with peppers, with tomato, battered and fried, in porrusalda — the recipes are endless. But none has the austere elegance of pil pil: the sauce that emerges from cooking cod in olive oil, gently perfumed with garlic and dried chilli. A piece of cod left to cook slowly over dying embers is probably where this minimalist masterpiece was born.

"There is something alchemical about the emulsion of a good pil pil. It forms slowly as the vessel is moved, with the temperature perfectly constant… it is not a mayonnaise; there is no solid body suspended in the oil. It is a sauce made exclusively from liquids." — Mark Kurlansky

Making the pil pil

Setting aside the fierce debates among celebrated Basque chefs, making a good pil pil is always a subject of passionate argument among Basques. A sauce that is simultaneously simple and fiendishly difficult, there are dozens of tricks for persuading it to emulsify: from the Argiñano method — stirring the oil with a colander after confiting the cod, reliably effective — to the use of syringes, or leaning on the gelatine-rich kokotxas (cod cheeks) to speed up the binding.

The trick that never fails

The one we want to share comes from Jon Egino, of the celebrated Egino salt cod shop in Portugalete. After two days of soaking — always in the fridge, changing the water every eight hours: morning, midday, and night — the key step is to dry the cod thoroughly, leaving it wrapped in cloths for a further six hours. This makes all the difference.

Next, cook the cod in olive oil over a gentle heat for around five minutes, then remove the pieces, lay them on a board, and let them drain properly — they will still release quite a bit of water, and every drop of it must go. Only then is it time to use the colander to stir the oil, return the well-drained pieces to the pan, and begin moving the cazuela in slow circular motions, adding the remaining oil little by little without stopping, until the sauce thickens into something rich and silky. Finish with the fried garlic and the chilli.

Don't be discouraged if it doesn't work the first time. Or the second. Trial and error is as valid in the kitchen as it is in science. And if the sauce seizes up on you, a quiet prayer to Jenaro Pildain — a legend of Basque gastronomy, revered above all for his mastery of salt cod — never goes amiss.

Pil pil is, at its heart, a lesson in Basque patience: very few ingredients, plenty of time, no shortcuts. And when it comes together, it is one of those dishes that explains why Basque cuisine has been the envy of the world for decades. If you ever find yourself in the Basque Country, order it. Better still, try to make it yourself.