Summary: Kokotxas al pil pil is one of the most emblematic dishes of Basque cuisine. This recipe teaches you how to prepare the perfect emulsion with cod or hake kokotxas, olive oil, and garlic, achieving that thick, silky sauce that is the hallmark of pil pil.
Table of contents
What are kokotxas and why are they so special
Kokotxas (also spelled cogote or cocochas in Spanish) are the fleshy part found on the underside of the jaw of cod and hake. It is a V-shaped muscle that the fish uses for gill movement, which gives it a unique texture: firm on the outside but extremely gelatinous and unctuous on the inside.
What makes kokotxas special is their high content of collagen and natural gelatin. When cooked at a low temperature in olive oil, they release this gelatin which, combined with the oil, forms the base of the pil pil emulsion. No other cut of fish has this natural emulsifying capacity.
In Basque cuisine, kokotxas are considered one of the most noble parts of the fish. Traditionally they were a humble product — fishermen separated them before selling the whole fish — but today they are one of the most sought-after pieces. A kilo of hake kokotxas can exceed €80 in the market, and cod kokotxas, although more accessible, are around €30-50/kg depending on quality and origin.
At Mercat del Ninot in Barcelona, we have been selecting the best kokotxas, both from Icelandic cod and Cantabrian hake, since 1990. The key is to choose fresh pieces, of good size and with intact skin, as it is precisely the skin that provides the most gelatin for the sauce.
Ingredients for kokotxas al pil pil
For 4 people
- 500 g cod kokotxas (or hake, fresh or defrosted)
- 200 ml extra virgin olive oil (mild, not spicy)
- 6 large garlic cloves, peeled and thinly sliced
- 1-2 dried chili peppers (cayenne or Basque chili)
- Salt (if using salted cod kokotxas, do not add)
Notes on ingredients
Olive oil: It is essential to use a mild extra virgin olive oil, arbequina variety or similar. A spicy or bitter oil will ruin the dish. The oil must be of good quality but does not need to be premium — it will be integrated into the emulsion and the nuances will be softened.
Kokotxas: Cod kokotxas are more gelatinous and emulsify more easily. Hake kokotxas are more delicate and have a finer flavor. Both work perfectly for pil pil, but the technique varies slightly (hake needs more patience).
Garlic: Sliced very thinly so that it releases all its flavor without burning. Garlic is the second pillar of pil pil along with the fish gelatin.
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Step-by-step recipe
Step 1: Prepare the kokotxas
If using salted cod kokotxas, you need to desalt them beforehand. Place them in a bowl with cold water in the refrigerator for 12-24 hours, changing the water 3-4 times. Fresh hake or fresh cod kokotxas only need a touch of salt before cooking.
Dry the kokotxas with paper towels. It is important that they are very dry so that the oil does not splatter and for the emulsion to form correctly. Set aside at room temperature while you prepare the garlic.
Step 2: Confit the garlic
Pour the olive oil into a wide earthenware casserole (or a wide pan) over very low heat. When the oil is warm (about 50-60°C), add the sliced garlic and chili pepper. Confit them over minimal heat for 3-4 minutes, until lightly golden. Do not burn them — burnt garlic would make the whole dish bitter.
Remove the garlic and chili pepper with a slotted spoon and set aside on a plate. The oil is flavored with garlic and chili, ready to cook the kokotxas.
Step 3: Cook the kokotxas
With the oil still over low heat (60-70°C, it should never boil), place the kokotxas in the casserole with the skin facing up. Cook them for 3-4 minutes on that side. You will see that they begin to release a whitish gelatin — this is the key to pil pil.
Carefully turn the kokotxas over (skin now facing down) and cook for another 2-3 minutes. The oil should be hot but never bubbling. The ideal temperature is between 60 and 70°C.
Step 4: Form the emulsion (the pil pil)
This is the crucial step. Remove the kokotxas from the casserole and set them aside on a plate, covered. In the casserole remains the oil with the gelatin released by the kokotxas.
Now you have two options:
Traditional method (earthenware casserole): Remove the casserole from the heat. Hold it by the handles and start making gentle circular movements, as if you were spinning a roulette wheel. The oil and gelatin will begin to bind, forming a whitish emulsion. This process takes 5-10 minutes. If the emulsion does not bind, place the casserole on the heat for a moment to warm it up and then move it off the heat again.
Alternative method (strainer): Strain the oil into a bowl. Place the casserole with the remaining gelatin over low heat. Gradually add the oil in a thin stream while moving the casserole in circles. It's the same principle as mayonnaise: gradually add the fat while emulsifying.
The sauce should have a texture similar to a light mayonnaise, with a white-yellowish color and creamy appearance.
Step 5: Plate
Return the kokotxas to the casserole with the pil pil sauce. Gently heat for 1-2 minutes without letting it boil. Add the reserved garlic and chili pepper on top. Serve directly in the earthenware casserole.
Tips for the perfect emulsion
The pil pil emulsion is the step that generates the most respect. These tips will help you achieve it:
- Always low temperature: If the oil is too hot, the gelatin denatures and does not emulsify. Never exceed 70°C.
- Earthenware casserole: Ceramic retains heat evenly and allows emulsion by thermal inertia. A steel pan cools too quickly.
- Patience: Emulsification can take 5-15 minutes. Don't despair. If it doesn't bind, stop, let it cool, and try again.
- Intact skin: The skin of the kokotxas is where the highest concentration of gelatin is. If they are skinned, the emulsion will be more difficult.
- Emergency trick: If it definitely doesn't bind, add a spoonful of cold fish broth to the hot oil and stir in gentle circles. The thermal shock helps to start the emulsion.
- Do not add flour or cornstarch: Authentic pil pil does NOT contain thickeners. The sauce thickens solely with the fish gelatin. If you need thickeners, it's not a pil pil.
Cod kokotxas vs hake kokotxas: differences
| Characteristic | Cod kokotxas | Hake kokotxas |
|---|---|---|
| Texture | More gelatinous, firm | More delicate, tender |
| Flavor | Intense, deep sea | Subtle, fine, elegant |
| Emulsion | Easier (more gelatin) | More difficult (less gelatin) |
| Size | Larger | Smaller |
| Price | €30-50/kg | €60-90/kg |
| Availability | Year-round (salted/frozen) | Seasonal (fresh) |
| Best for | Pil pil, green sauce | Green sauce, battered |
For pil pil, cod kokotxas are the most traditional option and the one that facilitates emulsion the most thanks to their higher gelatin content. Hake kokotxas give a more refined result but require more skill.
At Mercat del Ninot, we work with Icelandic cod kokotxas, selected for their size and freshness. Icelandic cod, caught in the cold waters of the North Atlantic, has firmer flesh and a higher gelatinous content than other origins, making it ideal for preparations like pil pil.
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Variations and accompaniment
Kokotxas in green sauce
The other great classic preparation. The emulsion is replaced by a green sauce made with fish broth, white wine, and abundant parsley. The result is a lighter, more herbaceous sauce. It can be made with the same kokotxas, adding a sauté of garlic and parsley, wetting with fish broth and fumet, and thickening with the fish's own gelatin plus a little flour.
Battered kokotxas
A simpler option: they are battered in flour and egg and fried in hot oil. They are crispy on the outside and gelatinous on the inside. They are perfect as a tapa or pintxo.
Recommended accompaniments
- Bread: Essential for dipping in the pil pil sauce. A good crusty country bread.
- Peas: Fresh peas are the classic accompaniment in the Basque Country.
- Asparagus: White asparagus from Navarra, grilled.
- Potatoes: Boiled potatoes cut into slices, to absorb the sauce.
- Wine: Young and fresh Txakoli, or a barrel-fermented white Rioja for a more complex pairing.
History of kokotxas in the Basque Country
Kokotxas have a fascinating history that reflects the evolution of Basque cuisine. For centuries, this part of the fish was discarded or given to the fishermen themselves as part of their ration. It was not considered a noble piece.
It was in the 1960s and 1970s that Basque chefs like Juan Mari Arzak and Pedro Subijana began to reclaim kokotxas as a haute cuisine ingredient. The New Basque Cuisine elevated them from a humble product to a gastronomic star, and the kokotxas al pil pil recipe became an emblem of Basque Country cuisine.
Today, kokotxas are protagonists in gastronomic societies in San Sebastián and Bilbao, in pintxo bars, and in Michelin-starred restaurants. Chefs like Martín Berasategui, Eneko Atxa, and Karlos Arguiñano regularly prepare them, each bringing their personal interpretation but always respecting the essence: quality product, precise technique, and respect for tradition.
In Barcelona, cod has a centuries-old tradition linked to Catalan cuisine — esqueixada, bacalao a la llauna, buñuelos de Cuaresma — and kokotxas have been integrated as a bridge between Basque and Catalan cuisine. At our stall in Mercat del Ninot, we have been preparing and selling cod kokotxas since 1990, and we have seen how demand has grown exponentially as more Barcelonians discover this gastronomic treasure.
Frequently asked questions
What exactly are kokotxas?
Kokotxas are the fleshy part located on the underside of the jaw of cod or hake. It is a V-shaped muscle with a high collagen and gelatin content, which gives it a unique texture: firm on the outside and extremely unctuous on the inside. They are one of the most valued parts of fish in Basque cuisine.
Why isn't my pil pil emulsion working?
The most common causes are: too high a temperature (the oil should not exceed 70°C), kokotxas with little skin (the gelatin is in the skin), too abrupt movements, or lack of patience. Tip: if it doesn't bind, add a spoonful of cold fish broth to the hot oil and stir in gentle circles.
Can frozen kokotxas be used for pil pil?
Yes, frozen kokotxas work well for pil pil. Thaw them slowly in the refrigerator for 12-24 hours, never in the microwave or at room temperature. Dry them well before cooking. The result is very good, although fresh ones have an extra touch of texture.
How much do cod kokotxas cost?
Cod kokotxas are around €30-50/kg depending on quality, size, and supplier. Hake kokotxas are more expensive, between €60-90/kg. For 4 people, you need about 500g, so the cost per person is about €4-6 with cod kokotxas.
What is the difference between pil pil and green sauce?
Pil pil is an emulsion of olive oil with fish gelatin, without water or broth. Green sauce is made with fish broth, white wine, parsley, and partially thickened with flour. Pil pil is more unctuous and intense; green sauce is lighter and more herbaceous. Both are classic Basque preparations.
Can I make pil pil with other fish?
Traditional pil pil is made with kokotxas or cod loins, as these are the parts with the most gelatin. However, it can also be made with hake, monkfish, or even prawns, although the emulsion will be less stable. Desalted salted cod gives the best result due to its high gelatinous content.
Conclusion
Kokotxas al pil pil are much more than a recipe: they are a cooking lesson in which three simple ingredients — kokotxas, olive oil, and garlic — are transformed into an extraordinary dish thanks to technique and patience. The key is quality product, controlled temperature, and respect for timings.
Don't be discouraged if the emulsion doesn't work out the first time. It's a dish that improves with practice, and each attempt will bring you closer to that creamy, silky texture that makes pil pil one of the great dishes of Spanish gastronomy. Start with cod kokotxas (they emulsify more easily than hake), use an earthenware casserole, and be patient. The result is worth every minute of dedication.
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