Cod with Tomato Arguiñano Style: Homemade Recipe Step by Step

Arguiñano and Cod with Tomato: A Television Classic

If there's one dish that defines Karlos Arguiñano's cooking, it's one that combines simplicity, color, and flavor in a single bite. Cod with tomato perfectly meets all three requirements: it's one of those stews he's prepared dozens of times on his TV show, always with minimal variations but with one unchangeable constant — respect for the product.

Arguiñano's philosophy with this dish is transparent: ripe tomatoes, patiently slow-cooked onions, peppers that add sweetness, and extra virgin olive oil that binds the entire sauce. No jarred sauces, no shortcuts. The result is a dish that smells of grandma's cooking and is prepared in less than an hour.

This recipe is inspired by Karlos Arguiñano's style; it's not a literal transcription of his program. We've adapted the proportions to use premium Icelandic cod loins, a product whose firm texture and clean flavor elevate any homemade preparation to another level.

At Bacalalo, we've been selecting the best Icelandic cod at Mercat del Ninot in Barcelona since 1990. For Arguiñano-style cod with tomato, thick loins are the perfect choice: they stay intact during cooking and absorb the tomato flavor without falling apart.

Ingredients for Arguiñano-Style Cod with Tomato

For 4 people

For the cod loins

• 4 Icelandic cod loins (approx. 200 g each, desalted)
• Flour for dredging
• Extra virgin olive oil

For the homemade tomato sauce

• 1 kg ripe tomatoes (plum or on the vine, very red)
• 2 large onions, thinly sliced
• 1 Italian green pepper, thinly sliced
• 1 red pepper, thinly sliced
• 4 cloves garlic, sliced
• 1 teaspoon sugar (to correct acidity)
• 100 ml extra virgin olive oil
• Salt and black pepper
• 1 bay leaf

Homemade Tomato Sauce: The Soul of the Dish

Arguiñano always says that "tomato sauce must be made with care and without haste." That's the secret: slow-cooking the vegetables until they release all their natural sweetness before adding the tomato.

Step 1: Confit the onion and peppers

In a large, shallow pot (like a rondeau or clay pot), heat 100 ml of olive oil over medium-low heat. Add the thinly sliced onion and peppers. Cook, stirring occasionally for 20 minutes, until the onion is completely translucent and the peppers are tender. Do not increase the heat: slow confit is the key to flavor.

When the vegetables are well cooked, add the sliced garlic and bay leaf. Cook for 2 more minutes until the garlic is fragrant but not browned.

Step 2: Add the tomato

Grate the tomatoes with a coarse grater, discarding the skin. Pour the grated tomato over the confited vegetables. Increase the heat to medium and cook for 25-30 minutes, stirring every few minutes. The sauce should reduce until it thickens considerably — it should have body, not be watery.

If the tomato is too acidic, add the teaspoon of sugar. Arguiñano almost always does this: "sugar doesn't sweeten, it corrects," he says. Season with salt and black pepper to taste.

Step 3: Optional — blend or leave rustic

Here you have two options depending on your taste. You can blend the sauce for a fine and silky tomato, or leave it chunky for a more rustic texture. In Arguiñano's style, the rustic version is more common: the pepper strips and onion add texture and presence to the dish.

Preparing the Cod Loins

If using dried cod, desalt it in cold water in the refrigerator for 48 hours, changing the water every 8-10 hours. If you buy pre-desalted cod, you can skip this step. In any case, dry them very well with paper towels before cooking.

Step 4: Sear the loins

Lightly flour the cod loins, shaking off any excess. In a wide pan with a generous amount of olive oil (Arguiñano never skimps on oil), sear the loins first on the skin side for 2 minutes. Flip and sear on the flesh side for 1 more minute. Don't aim to cook them all the way through — just sear them to get a golden crust and prevent them from falling apart in the sauce.

Remove the loins and set aside on a plate. The inside should still be raw: it will finish cooking in the tomato sauce.

Step 5: Cook in the sauce

Place the seared loins over the tomato sauce in the pot. Cover and cook over low heat for 10-12 minutes. The loins should finish cooking slowly, absorbing the flavor of the tomato without losing their internal juiciness.

If the sauce is too thick, add a couple of tablespoons of water or fish broth. The cod will also release some juices that will enrich the sauce.

Final Assembly and Presentation

Arguiñano-style presentation is generous and colorful, without unnecessary flourishes. Serve directly from the pot or distribute into individual deep plates:

• A generous bed of tomato sauce at the bottom of the plate
• The cod loin on top, with the golden skin visible
• A drizzle of raw extra virgin olive oil over top
• Sprinkled fresh chopped parsley
• A few strips of confited pepper decorating the loin

Serve with rustic bread for dipping in the sauce. As Arguiñano says, "the best part is the bread with the sauce." Panadera potatoes or white rice are also perfect side dishes.

Arguiñano's Tips for Perfect Cod with Tomato

• Always use ripe tomatoes: The secret to a good tomato sauce is to use very ripe, red tomatoes. If they're not in season, canned plum tomatoes are a better option than bland greenhouse tomatoes.
• Confit, don't fry: The vegetables are slow-cooked, never fried. High heat caramelizes too quickly and produces bitterness instead of sweetness.
• Generous olive oil: Arguiñano never skimps on oil. Tomato sauce needs it to bind and have body. Oil is not a secondary ingredient; it's a protagonist.
• Sear before stewing: Lightly flouring and briefly searing the loins creates a protective layer that keeps the cod juicy within the sauce. Without this step, the cod falls apart.
• Low heat to finish: The last 10-12 minutes of cooking should be over very low heat. The cod cooks with the residual heat of the sauce, not with an aggressive boil.
• Pinch of sugar: Don't be afraid to correct the acidity of the tomato with a little sugar. It's a classic technique that Arguiñano almost always uses.
• Rest before serving: Let the dish rest for 5 minutes off the heat before serving. The sauce settles, the flavors integrate, and the cod finishes cooking with the residual heat.

For an exceptional result, the quality of the cod makes all the difference. Bacalalo's Icelandic cod loins have the firm texture and clean flavor this dish needs: they stay intact in the sauce and absorb all the tomato flavor without falling apart.

What Spices Go into Cod with Tomato?

Arguiñano-style cod with tomato is deliberately simple in spices: it lets the product and the soffritto speak for themselves. The essential ones are a bay leaf (which perfumes the sauce during cooking), freshly ground black pepper, and, of course, salt. From there, you can customize without distorting the dish:

• Sweet paprika from La Vera: half a teaspoon added with the garlic provides color and a very Spanish smoky undertone.
• A pinch of sugar: it's not a spice, but it corrects the acidity of the tomato, as Arguiñano always does.
• Fresh chopped parsley: raw at the end, for freshness and color.
• Chili or cayenne pepper: optional, if you like a spicy touch, similar to cod with garlic.

Avoid highly aromatic spice blends (cumin, curry, Herbs de Provence): they mask the clean flavor of Icelandic cod, which is precisely what we want to highlight.

Variations: With Potatoes, With Peppers, and Grandma's Recipe

Cod with tomato allows for variations that turn it into a standalone dish or regional versions. These are the most sought-after:

• Cod with tomato and potatoes: add thick-sliced potatoes to the tomato sauce and cook for 15 minutes before incorporating the cod. It becomes a complete one-pot meal.
• Cod with tomato and peppers: the version already included in this recipe. Enhance with strips of roasted red pepper on top for a more striking presentation.
• Grandma's recipe: the most traditional version uses only tomato, onion, garlic, and good oil, without peppers. Long slow-cooking and very reduced tomato: pure old-fashioned cooking.
• Baked: pour the sauce into a dish, place the seared loins on top, and bake at 180°C for 15-18 minutes.

In all variations, the key is the same: a slow-cooked soffritto and quality cod that holds up to cooking without falling apart.

Frequently Asked Questions