I cooked peixe a pil pil tonight for dinner for the second time in two days. It's a dish I’ve been thinking about recently, one we used to cook often on Mondays at Chez Panisse, when to our delight and that of the customers we would step away from France and cook food from other parts of the Mediterranean. Pil pil is a Basque miracle of salt cod or bacalão cooked very slowly with mild guindilla red pepper and garlic in olive oil in a cazuela on top of the stove. Pil pil refers to the sauce, properly speaking, not the entire dish.

Deviating from the original recipe, I bought fresh local rockfish not salt cod. Rockfish is a favorite of mine,  caught here in Bolinas. I salted it lightly 6 hours ahead of cooking. Rockfish are found almost exclusively in the Pacific ocean. Everything about them is good: they're from nearby, as fresh as can be, with firm white flesh that requires the long cooking that defines this dish and … it’s inexpensive, though not as inexpensive as it used to be. (Read on and you’ll see why.) I substituted green garlic, so delicious and joyous in the markets now, for the head garlic that's from last year or from very far away. I tossed in few crushed, very fragrant coriander seeds grown and given me by an old friend, and one bay leaf. after it was cooked I sprinkled a whisper of chopped wild fennel fronds on top.

There are 100 species of rockfish in the genus Sebastes, of many colors, sizes, shapes and, literally, stripes. They vary dramatically in size, up to about 30 pounds, but fish that size are unusual. Most are caught inshore, to a depth of about 600 ft. Rockfish are the most abundant fish species in the Pacific but they’ve been heavily fished. Quite a few varieties -- 13, I believe -- are allowed the market names “rock cod” and “Pacific red snapper,” and the success of those market names has been the reason for the heavy fishing. Depleted stocks have caused California Fish and Game to impose restrictions that dictate in which areas, with which gear, and which varieties of rockfish may be caught. The goal of the restrictions is to protect the populations of several species in particular, but especially the yellow eye rockfish. It is also intended to limit rapacious, destructive trawl fishing. Rockfish harvest has dropped dramatically and forced the price up as a result. The moratorium is a needed restriction. I just hope Monterey Bay squid isn’t next.

The origin of the name pil pil is something that cannot be known (one of my favorite phrases and notions, from philosophy days). It is said to be an onomatopoeic, imitating the sound of fish sizzling gently in oil in an earthenware crock. Perhaps that’s the answer. I would like to put my finger on the name’s nascence but I don’t believe that's possible; it’s a buried truth lost to history. In fact the fish doesn’t really sizzle in the pan any longer; the sauce has become a silky, opaque sauce, an emulsified not clear one, as it once was. It is now ligado, or bound, thickened within itself This happened in late 19th Century, when San Sebastián cooks were said to be falling under the influence of French chefs in their use of sauces. Many cooks would like to called French-influenced, but in Basque country this was not a compliment or a universal desire.

The technique of this dish is the important part. Many sources say it takes an hour to swirl the sauce into its proper consistency but it takes me only about 25 minutes or so, depending on the thickness of the fillets; I’ve made it a lot so that's a pretty accurate description. And that's without trying to rush the dish in any way. 25 minutes seems a long time for fish to cook but keep in mind that traditionally it’s made with salt cod, a typically long-cooked fish, and the heat is kept very low. This is exactly why I like rockfish: it needs to be cooked through or it can be rubbery. At first it tenses up but when it faces its final demise, it relaxes and becomes tender and giving, just like salt cod.

You swirl and swirl pil pil in circles in its cazuela over a very gentle heat. To me, the swirling has the soothing, repetitive sound of its own name if you say it softly -- pil pil pil pil --  almost like rain, as the cazuela lightly brushes  the stove or counter top as the oil and fish liquor begin to commingle. You may have moved it off the stove, as i often do, if you're being careful with the temperature of the crock, then back again to the stove. It happens all of a sudden. At the moment when the fillet is almost completely cooked through its juices begin to run and the sauce comes together, in a blink. Truthfully, this constant swirling is only an affectation; as with risotto and its supposed requisite relentless stirring, the lore is richer than the dish itself. The swirling does not need to be constant, just attentive. It’s a simple matter, really. I could mention physics here, but I don’t want to lose the cooks in the audience, and I’m not Harold McGee. Thankfully. Anyway, concocting a pil pil is more akin to alchemy.

Temperature is a critical factor, and I realized one day many years ago why so many pil pils are broken: the crock is let to go too hot. This particular day as I was swirling, it came to me that pil pilPil pil is the lightest possible emulsion, much lighter than its cousin (by marriage only) beurre blanc. There are no eggs, no milk solids from the melted butter, no liquid component from the wine, though there is the scant juice the fish gives up. Pil pil is so delicate and fine nothing can approach it. Of course because of this simple purity one’s oil has to be of the highest quality and not a spicy, peppery Tuscan or Umbrian sprite, nothing from the warm south, but something light and heavenly, as an oil from Liguria. That’s what I prefer.

Pil pil has in an existential purity parallel to that of ali-oli, the truest version of which is made without egg yolk, though few chefs, even Spanish ones, make it in this ancient way. Blenders and food processors of the most modern type have taken over the kitchens of Europe in the same way they have in America, and perhaps even more so; they’ve destroyed tradition and precluded the cook’s understanding of kitchen fundamentals.

Contrast beurre blanc to pil pil. In French cooking, surprisingly, purity vanishes. Beurre blanc, though a fine sauce, is held together with egg yolk. Not a sin, just not the ultimate, mysterious simplicity – and challenge! -- of pil pil or ali-oil. Beurre blanc has many secret cheats, the most upsetting of which is the addition of cream to its base to hold it together. This not only changes the sauce but also encourages the cook toward laziness, driving one him or her to become one who no longer has to pay careful attention to his or her sauce or the centuries-old technique that created it. This tragic method is sometimes used with pil pil as well.

Mark Kurlansky has written in staggering detail about the Basques and cod fish. There is a claim in his book “The Basque History of the World” with which I disagree. In his discussion of pil pil he says it “is not a mayonnaise” (true, no quibble) but goes on to say “there’s no solid suspended in the oil.” Well, an emulsion is not a suspension, and even letting that one go, is the liquid provided by the cooked fish any less a “solid” than the egg yolk? Maybe it’s a bit thinner, but is egg yolk a solid? Not for me. Weren’t we taught in science physics class that the transition from gas to liquid to solid is a continuum anyway? Whew! I think I need to get out more. 

Don’t take me wrong: I like Kurlansky’s writing and have read “Cod: A Biography of the Fish that Changed the World” twice. It’s just that we need to be careful with our ideas, the way our friend Harold McGee usually is. It's a moral and social responsibility. 

Pil pil is a delight no one should pass up. It seems difficult but it is as easy a pie. Give it a try, but be patient with it.