Cod collar in green sauce is one of the most unknown gems of Basque cuisine. This gelatinous, collagen-rich cut melts in your mouth with an intensity of flavor that no other part of the cod can match. I'll explain exactly what the cod collar is, why it's so special, and how to prepare it in green sauce using the koxkera technique to achieve an authentic result.
Table of Contents
- What is cod collar and why is it so special
- Cod anatomy: where is the collar located
- Ingredients for 4 servings
- Step-by-step: cod collar in green sauce
- The koxkera technique: how to thicken the sauce
- Difference between cod collar and kokotxas
- Where to buy quality cod collar
- Variations and accompaniments
- Frequently asked questions
- Conclusions
What is cod collar and why is it so special
Cod collar is the piece that connects the head to the loin of the fish. It's an anatomical transition area that accumulates an extraordinary amount of collagen, natural gelatin, and intramuscular fat. In culinary terms, it's the tastiest part of the entire cod.
If the loin is the noble and clean part, the collar is the soulful part. Its texture is unique: when cooked, the collagen transforms into gelatin, creating a creaminess that coats the palate. It's the same reason why osso buco is better than sirloin for a stew: connective tissue, far from being a defect, is the secret to flavor.
In Basque cuisine, cod collar holds the status of a delicacy. Good restaurants in Bilbao and San Sebastián offer it as a star dish, and it's not uncommon for it to cost more than the loin. Because whoever has tried it knows there's no going back.
A cut for connoisseurs
The cod collar is not a popular cut outside the Basque Country and some gastronomic circles. Most people buy cod loins or flakes and are unaware that this cut exists. That is, paradoxically, an advantage: being less in demand, its price is more accessible than that of kokotxas, and its flavor is just as spectacular.
At Mercat del Ninot, we've been advising customers for decades who come asking for loin and leave with collar after trying it. It's a conversion that always happens in the same direction.
Cod anatomy: where is the collar located
To understand the collar, you need to understand the cod's structure:
- Head: Contains the kokotxas (lower jaw), snouts, and cheeks. Small, very gelatinous pieces.
- Collar: The area immediately behind the head. Thick, triangular piece, with lots of collagen and large bones that are easy to remove. Weighs between 200 and 400 g depending on the size of the cod.
- Loin: The central, clean piece, with defined flakes. It is the most commercial part.
- Tail: Thinner and more fibrous. Ideal for flaking or brandade.
- Tripe (stomachs): The stomach lining. Gelatinous texture, highly prized in haute cuisine.
The cod collar is visually distinguished by its more irregular shape than the loin, its variable thickness, and the presence of cartilages and large bones that are easily removed after cooking. Do not try to clean them before cooking: those cartilages add gelatin to the juice.
Salted Cod Cheeks (Kokotxas) - 500g
Available on Bacalalo.com with refrigerated 24-48h shipping
Ingredients for 4 servings
- 4 desalted cod collars, 200-250g each
- 6 tablespoons extra virgin olive oil
- 4 cloves garlic, thinly sliced
- 1 dried cayenne pepper (optional, for a subtle spicy kick)
- 200 ml fish stock (or homemade fumet)
- 1 large bunch fresh parsley (about 40g, leaves only)
- 150g fresh or frozen peas
- 8 asparagus tips (optional)
- 2 tablespoons wheat flour
- 100 ml dry white wine
- Salt (adjust at the end, cod already has residual salt)
About the fish stock
If you have cod bones and heads, make a quick fumet: cook for 20 minutes with onion, leek, carrot, and a splash of white wine. Strain and use it. This stock exponentially enhances the green sauce. If you don't have it, a quality commercial fish stock works, but add less salt to the recipe.
Step-by-step: cod collar in green sauce
Step 1 — Prepare the base sauté (5 minutes)
In an earthenware casserole or a wide, shallow pan, heat the olive oil over medium-low heat. Add the sliced garlic and the chili. Cook for 2 minutes, stirring constantly, until the garlic is pale golden. Do not burn it: burnt garlic will make the whole sauce bitter.
Remove the chili (it has already released its spice). Add the flour and stir for 30 seconds to integrate it with the oil without forming lumps.
Step 2 — Create the green sauce base (5 minutes)
Turn the heat up to medium and add the white wine. Let the alcohol evaporate for 1 minute, stirring. Gradually add the fish stock, stirring constantly. Finely chop half of the parsley and add it. Reduce the heat and let the sauce simmer gently for 3 minutes.
Step 3 — Cook the cod collars (12-15 minutes)
Place the cod collars in the casserole, skin-side up, partially submerged in the sauce. Cover the casserole and cook over low heat for 12-15 minutes. After 8 minutes, add the peas and asparagus tips if you are using them.
During cooking, move the casserole in gentle circular motions every 3-4 minutes (the swaying motion). This movement is essential for the gelatin from the cod collar to emulsify with the sauce and thicken it naturally. Do not use a spoon: wrist movement is the correct technique.
Step 4 — Thicken the sauce (the koxkera)
When the cod collars are cooked (the meat separates easily from the central bone), check the sauce. It should have a texture between liquid and creamy, with a characteristic sheen. If it's too liquid, slightly increase the heat and continue the swaying motion for 2-3 more minutes. The gelatin from the cod collar should have naturally thickened the sauce.
Step 5 — Finishing touch
Remove from heat. Finely chop the remaining parsley and sprinkle it generously over the cod collars. Let it rest for 2 minutes before serving: the sauce will continue to thicken off the heat.
Serve directly in the earthenware casserole if you used one. Cod collar in green sauce is eaten with bread, lots of bread, so as not to leave a single drop of sauce.
The koxkera technique: how to thicken the sauce
The koxkera (or Basque green sauce) is one of the great techniques of Spanish cuisine. Its secret is not any artificial thickener: it is the natural gelatin of the fish which, through the circular motion of the casserole (the "vaivén"), emulsifies with the olive oil and creates a silky and shiny sauce.
Keys to making it work:
- Low heat. If the sauce boils vigorously, the emulsion breaks.
- Constant movement. Shake the casserole every few minutes with a wrist rotation. Do not stir with a spoon.
- Gelatinous pieces. Cod collar and kokotxas are ideal pieces because they release more gelatin. A clean loin will not thicken the sauce in the same way.
- Patience. The emulsion takes 8-10 minutes to form. Don't rush it.
If the sauce still doesn't thicken, there's an emergency trick: dissolve half a teaspoon of cornstarch in a tablespoon of cold water and add it to the sauce. But with quality cod collar, it shouldn't be necessary.
Difference between cod collar and kokotxas
| Characteristic | Cod Collar | Kokotxas (Cod Cheeks) |
|---|---|---|
| Location | Between head and loin | Chin (lower part of the head) |
| Size | 200-400 g per piece | 15-30 g per piece |
| Texture | Gelatinous + meaty | Very gelatinous, almost melting |
| Flavor | Intense, complex | Delicate, mild |
| Price | Moderate | High (scarce cut) |
| Bones | Large, easy to remove | Boneless |
| Best preparation | Green sauce, baked, stewed | Green sauce, battered, tempura |
If kokotxas are the caviar of cod, the cod collar is its Iberian ham: more substantial, with more character, and with an unbeatable quality-price ratio.
Where to buy quality cod collar
Cod collar is not sold everywhere. Supermarkets rarely offer it because it's a piece that requires knowledge to cut and desalt correctly. You'll find it at:
- Specialized cod fishmongers — Like us at Mercat del Ninot. We cut the collar to size and desalt it artisanally.
- Municipal markets — Traditional cod stalls usually have it if you ask.
- Specialized online stores — Refrigerated shipping, with desalting included.
When buying cod collar, look for white, firm flesh, without yellowish areas (a sign of oxidation). The thickness should be at least 4 cm at the widest part. And make sure it is properly desalted: a salty collar will ruin any recipe.
Variations and accompaniments
Baked cod collar with panadera potatoes
Place the cod collar on a bed of thinly sliced potatoes (3 mm), julienned onion, and green pepper. Drizzle with oil and white wine. Bake at 180 °C for 35-40 minutes. The potatoes absorb the gelatinous juices from the cod collar and are extraordinary.
Cod collar in choricero pepper sauce
Replace the parsley with the flesh of 4 rehydrated choricero peppers. The result is a Vizcaína sauce adapted to cod collar, with more body and a spectacular dark red color.
Recommended accompaniments
- Boiled potatoes mashed with a fork and a drizzle of oil (the classic Basque way)
- Crusty country bread for dipping in the sauce
- Roasted piquillo peppers as a side garnish
Frequently asked questions
Does cod collar have many bones?
It has large bones that are easy to locate. The central bone is removed in one piece after cooking. It doesn't have the fine, treacherous bones of other parts of the fish. It's a much easier piece to eat than it seems.
Can I use cod loin instead of cod collar for this recipe?
You can, but the result will be different. The loin doesn't have the gelatin of the collar, so the sauce won't thicken naturally and you'll need more flour or cornstarch to thicken it. The flavor will also be less intense. If you only have loin, the recipe works, but it loses its essence.
How long does cod collar take to cook?
Between 12 and 15 minutes over low heat, covered. It depends on the thickness. You know it's ready when, pressing gently with a spoon, the meat separates from the bone without resistance. Don't overcook it or it will lose texture.
What exactly is koxkera?
It is the Basque technique for thickening sauces by means of the circular movement of the casserole (vaivén). The gelatin from the fish emulsifies with the oil and broth, creating a creamy sauce without the need for cream, butter or thickeners. It is the basis of green sauce and pil-pil sauce.
Can cod collar in green sauce be frozen?
I don't recommend it. The emulsified sauce breaks when thawed, and the cod collar loses its gelatinous texture. It's a dish that should be consumed freshly made. If you have leftovers, consume them the next day by reheating very gently over low heat.
Is cod collar more expensive than loin?
Generally not. Cod collar is usually cheaper than loin because it is less known and has a less "clean" presentation. It is one of the best value-for-money cuts of cod. In high-end restaurants, however, it can be priced even higher than the loin.
What wine pairs well with cod collar in green sauce?
Txakoli is the classic option and works perfectly. Also a young Albariño or a Verdejo from Rueda. If you prefer something fuller-bodied, a Godello from Valdeorras complements the creaminess of the sauce. Avoid red wines with this dish.
Conclusions
Cod collar in green sauce is one of those dishes that separates amateurs from true gastronomy lovers. It's not the prettiest part of the cod, nor the best known, but it is, without a doubt, the most delicious.
The combination of its gelatinous texture with the Basque green sauce creates a dish with a depth of flavor that cannot be achieved with any other cut. And the koxkera technique, although it requires practice, is accessible to any home cook with patience.
If you've never tried cod collar, I invite you to give it a try. You'll likely never look at a cod loin the same way again.
Related articles:
Marc González Sáez — Bacalalo, Mercat del Ninot, Barcelona. Since 1990.
