Atún de Almadraba Encebollado

Ingredients

Equipment Needed

• •Wide heavy sauté pan with lid, 28 to 30cm
• •Sharp chef's knife
• •Tongs or slotted spoon
• •Instant-read thermometer, optional

Instructions

1. 1

   Prepare the tuna

   Cut the tuna across the grain into even 4cm pieces. Pat them thoroughly dry and season with 5g of the salt. Leave them for 10 minutes while you slice the onions. Pésalo, no lo adivines, weigh it rather than guessing; pieces of one size finish together.

   Remove any dark bloodline or tough white sinew. Both tighten during cooking and distract from the clean taste of the tuna.
2. 2

   Mark the tuna

   Heat 50ml of the olive oil in a wide heavy pan over medium-high heat. Sear the tuna in two batches, about 30 seconds on each of two broad sides. The surface should colour lightly while the middle remains raw. Lift each batch onto a plate immediately and keep every drop of juice it releases.

3. 3

   Soften the onions

   Lower the heat to medium-low and add the remaining 25ml olive oil, the onions, garlic, bay leaves, and remaining 5g salt. Turn everything through the tuna-flavoured oil. Cover and cook for 15 minutes, stirring every 5 minutes, until the onions have collapsed and released their liquid.

4. 4

   Cook until dark gold

   Remove the lid and continue cooking the onions over low heat for 15 to 20 minutes. Stir more often as their liquid disappears. They are ready when very soft, dark gold, and sweet, with no pale raw crunch left. This slow cebolla pochada, the gently cooked onion base, is the part that decides the dish.

   If the bottom catches before the onions soften, add one tablespoon of the measured water and scrape gently. Do not turn up the heat to hurry them.
5. 5

   Wake the spices

   Crush the oregano between your fingers and stir it into the onions. Take the pan off the heat, add the sweet pimentón, and stir for 15 seconds. Keeping the pan away from direct heat here prevents the pimentón from scorching and turning bitter.

6. 6

   Build the onion sauce

   Return the pan to medium heat and pour in the wine and sherry vinegar. Let them bubble for 3 minutes, scraping up the browned traces from the bottom. Add the 100ml water, lower the heat, and cook uncovered for 5 to 7 minutes. The onions should be loose enough to spoon yet glossy rather than watery.

7. 7

   Finish the tuna

   Nestle the tuna and its collected juices into the onions in one layer. Turn each piece once and cook gently for 1½ to 2 minutes, just until the outside is cooked and the centre remains rosy, about 48 to 52°C on an instant-read thermometer. Remove the pan from the heat at once and let it settle for 2 minutes before serving.

   Yellowfin is leaner than red tuna, so begin checking after 1 minute. For anyone who should avoid undercooked fish, cook the centre to 63°C; it will be firmer, but safety comes first.
8. 8

   Serve with the onions

   Spoon the onions generously over and around the tuna, giving everyone some of the wine-darkened juices. Serve at once with plain boiled potatoes, fried potatoes, or sturdy bread. The onions may wait at the table. The tuna will not.

Chef Tips

• •Almadraba names the seasonal net fishery, not a species or a cut. Ask for traceable Atlantic bluefin loin from a legal fishery, ideally during the spring Cádiz season, and avoid the fatty ventresca for this dish; it deserves gentler treatment.
• •Good frozen tuna is entirely proper here. Thaw it overnight on a rack in the refrigerator, then dry it very well. Frozen bluefin keeps the richness of the Cádiz fish; yellowfin is lighter and dries sooner.
• •Use 900g peeled onion, not four onions guessed by size. They shrink to a fraction of their volume and form the sauce, so what looks excessive at the start is correct.
• •Manzanilla from Sanlúcar or fino from Jerez gives the sauce the driest, most local character. Any dry, unoaked white wine works, but the finished sauce will lose some of that saline edge.
• •Keep leftovers covered in the refrigerator for no more than one day. Eat them cool or warm the onions separately before folding in the tuna; boiling the whole dish again turns the fish dry.

Advance Preparation

• •The onions can be cooked through the wine-and-water stage up to one day ahead. Refrigerate them covered, then return them to a gentle simmer before searing and adding the tuna.
• •The tuna may be trimmed and cut up to two hours ahead. Keep it covered in the coldest part of the refrigerator, then salt it only 10 minutes before cooking.
• •If serving with boiled potatoes, cook them earlier the same day and warm them in a spoonful of the onion sauce just before the tuna goes back into the pan.

Frequently Asked Questions

Nutrition Information

1 serving (about 360g)