Cod with "Choricero" Pepper Skin: High Cuisine Trompe L'oeil

What is a trompe l'oeil in cooking

A trompe l'oeil is a culinary technique that consists of presenting a dish with the appearance of something it is not. The name comes from pictorial art ("trompe-l'oeil" in French: "deceives the eye") and in cooking, it is used to surprise the diner: what looks like an olive is actually an oil sphere, what looks like a fried egg is a mango and yogurt dessert.

In the case of the cod with choricero pepper skin, the trompe l'oeil works on two levels. At first glance, it looks like a classic stuffed pepper: red, shiny, with a convex shape. But when cut with a knife, instead of finding minced meat or rice, a confited cod loin appears, white, silky, which dramatically contrasts with the outer red layer.

This dish has its origins in avant-garde Basque cuisine, where chefs like Martín Berasategui and Eneko Atxa have explored the relationship between cod and choricero pepper (which are already a classic pair in Basque cuisine) taking it to a higher technical level. Bacalao a la vizcaína is the traditional version; the trompe l'oeil is the 21st-century version.

The choricero pepper: the taste of the Basque Country

The choricero pepper is a variety of red pepper that is air-dried for weeks until it loses all its moisture. The result is a wrinkled, almost crispy skin, with a sweet, smoky, and deep flavor unlike any other pepper.

It is called "choricero" because it is traditionally used to color and flavor Basque chorizo, but its use in cooking goes far beyond. It is the star ingredient of vizcaína sauce (which does not contain tomato, but choricero), marmitako, Tolosa beans, and dozens of stews from northern Spain.

For this recipe, we need the choricero pulp: that red flesh that remains after scraping the inside of the rehydrated pepper. It is the base of the puree that we will gel to create the fake skin. Buy quality choriceros (those from Ibarra or Gernika are the best) or, failing that, pre-packaged choricero pulp, which saves work.

Complete ingredients (4 people)

For the choricero skin (gelled)

• 12 dried choricero peppers (or 200 g of packaged choricero pulp)
• 200 ml of soaking water from the peppers
• 4 g of agar-agar powder (2% of the total liquid weight)
• 1 teaspoon of olive oil
• A pinch of salt

For the confit cod

• 4 desalted cod loins of 180-200 g each (uniform thickness)
• 300 ml of extra virgin olive oil (mild, arbequina)
• 2 crushed garlic cloves
• 1 dried chili pepper (optional)

For the accompanying sauce

• 100 ml of cod cooking broth (or fish fumet)
• 50 g of choricero pulp (reserved from step 1)
• 30 ml of cod confit oil
• Salt, pepper

Garnish

• Confit potatoes (diced, confited in oil at 80 °C)
• Grilled spring onion
• Fresh parsley leaves

Step 1: Choricero pepper puree

If using dried choricero peppers (recommended, better flavor than packaged pulp):

1. Rehydrate the peppers: place them in a bowl with hot (not boiling) water for 30 minutes. They should be soft and flexible.
2. Scrape the pulp: open each pepper in half, remove the seeds, and with a spoon, scrape the red flesh from the inside of the skin. Discard the skins (or save them for broths). You should get about 200 g of pulp.
3. Reserve the soaking water: filter it through a fine sieve (it may have seeds or impurities). You need 200 ml.
4. Blend the pulp with the 200 ml of soaking water until you get a completely smooth puree, without lumps. Pass it through a fine sieve or a chinois if necessary: for gelling, the texture must be perfectly homogeneous.

If using packaged choricero pulp, simply dilute it with 200 ml of hot water and blend until homogeneous.

Step 2: Gelling with agar-agar (the fake skin)

This is the most technical phase of the recipe. Agar-agar is a plant-based gelling agent (extracted from red algae) that forms firm yet elastic gels when cooled. Unlike animal gelatin, agar-agar gels at room temperature and remains solid up to 85 °C, allowing us to wrap hot cod without the skin melting.

1. Place the choricero puree in a saucepan and heat over medium heat until it begins to bubble gently.
2. Add the agar-agar powder (4 g) little by little, stirring constantly with a whisk. The agar-agar must boil for at least 2 minutes to be fully activated. If it does not boil enough, it will not gel.
3. Add the teaspoon of oil and the pinch of salt. Mix well.
4. Immediately pour onto a baking sheet lined with acetate paper or very taut cling film. The thickness of the layer should be 2-3 mm: neither thicker (it would be gummy) nor thinner (it would break when wrapping).
5. To achieve uniform thickness, tilt the tray to distribute the liquid. Work quickly: agar-agar begins to gel from 40 °C.
6. Let cool at room temperature for 15-20 minutes. The surface will go from liquid to firm. When you can lift a corner without it breaking, it's ready.

Critical point: the proportion of agar-agar determines the texture. With 2% (4 g per 200 ml), you get a flexible sheet that can be folded and wrapped. With 1%, it would be too soft; with 3%, stiff and brittle. If it's your first time, do a small test first.

Step 3: Confit cod at low temperature

The cod is confited while the choricero skin cools. Low-temperature confiting is the perfect technique for this dish because it achieves a silky, moist, and flaky interior that contrasts with the firm outer layer.

1. Put the olive oil in a saucepan with the garlic cloves and the chili pepper. Heat to 65 °C.
2. Introduce the cod loins completely submerged.
3. Cook for 12-15 minutes maintaining the temperature between 62 and 68 °C. Use a thermometer.
4. Remove the loins and place them on absorbent paper for 2 minutes. Reserve the confit oil (you will use it for the sauce).

The cod should be cooked but slightly translucent in the center. When wrapped with the skin and briefly reheated, it will finish cooking. If you overcook it now, it will be dry when served.

Step 4: Wrapping the cod with the skin

1. Cut the choricero sheet into rectangles large enough to wrap each cod loin: calculate the perimeter of the loin + 1 cm overlap on each side.
2. Place a cod loin in the center of each choricero rectangle. The nice part of the cod (what used to be the skin) should be against the red sheet.
3. Wrap carefully, gently pressing the choricero sheet against the cod. The gelatin on the surface of the cod (still warm) helps the skin to adhere. Fold the ends as if wrapping a gift.
4. Seal with heat: briefly pass each piece over a hot pan (without oil) for 10-15 seconds on each side. The heat slightly melts the surface of the agar-agar and seals it against the cod. Don't overdo it: if the agar exceeds 85 °C, it melts.
5. Reserve the pieces in an oven at 60 °C while preparing the sauce.

Step 5: Plating and garnishes

The sauce (3 minutes)

1. In a saucepan, mix the cooking broth (or fumet), the reserved choricero pulp, and the confit oil.
2. Heat and emulsify with a hand blender until a homogeneous, shiny, reddish-orange sauce is obtained.
3. Adjust salt. It should be intense but not aggressive: it's an accompaniment, not the star.

Assembly

1. Pour 2-3 tablespoons of sauce onto the base of the plate.
2. Place the wrapped loin in the center, with the cut visible: that is, cut a corner of the wrapped cod so that the red exterior / white interior contrast is visible. This is the "reveal" of the trompe l'oeil.
3. Arrange the confit potatoes and grilled spring onion around it.
4. Finish with parsley leaves and a drizzle of confit oil.

The moment of serving is the moment of truth: when the diner cuts the piece and discovers the white interior wrapped in the red sheet, the effect is immediate. It is a dish that generates conversation, that is photographed, and that shows that cod cuisine can be as sophisticated as any luxury protein.

The science of agar-agar: how it works

Understanding agar-agar will help you master not only this recipe but any gelling technique.

• Origin: it is extracted from red algae of the genus Gelidium and Gracilaria. It is 100% vegetable (suitable for vegans).
• Activation: it needs to boil for at least 2 minutes at 85-100 °C for the molecules to unfold and form the gelling network.
• Gelling: it forms a gel when cooled below 40 °C. Unlike animal gelatin (which gels at 15 °C), agar-agar is much more robust.
• Melting: agar-agar gel melts at 85 °C. This means you can reheat a dish without the gel dissolving, as long as you don't exceed that temperature.
• Texture: firm, clean, slightly brittle. It is not elastic like gelatin. That's why the proportion matters: too little agar and it won't gel; too much and it will be like plastic.
• Standard dosage: 1-2% for soft gels (flexible sheets), 2-3% for firm gels (spheres, cubes), 0.5-1% to thicken liquids without fully gelling.

Variations and other edible skins

• Squid ink skin: replace the choricero puree with squid ink diluted in fish broth. The sheet comes out black, shiny, with an intense marine flavor. The contrast with white cod is dramatic.
• Piquillo pepper skin: blend jarred piquillos with their juice, gel the same way. The result is sweeter and milder than choricero.
• Beetroot skin: gelled cooked beetroot puree. Intense magenta color, earthy flavor that combines surprisingly well with cod.
• Saffron skin: concentrated saffron infusion in gelled broth. Golden color, floral flavor. For gala presentations.
• Without agar-agar: if you don't want to use gelling agents, you can make a simplified version: confit the cod, place it on a bed of thick choricero puree, and gratin for 2 minutes so that the puree adheres to the surface. It's not a true trompe l'oeil, but the flavor is very similar.

Frequently asked questions