Baked Tuna with Tomatoes and Green Olives

Fresh tuna, a tomato sauce sharpened with garlic and chilli, and a good handful of green olives baked into it — this is coastal Mediterranean home cooking at its most forgiving. Get the olives right and the dish sings.

This is the kind of dish that turns up all round the northern Mediterranean under a dozen names: a piece of firm fish laid in a simple tomato sauce and finished in the oven. The tuna gives it substance, the tomato gives it acidity, and the green olives do the real work — a briny, savoury lift that keeps the whole plate from going flat. It asks almost nothing of the cook, which is exactly why the quality of each ingredient shows so plainly.

Choosing the olive

A cooked sauce is unkind to a soft, mild olive: it goes to mush and gives up its character to the tomato. You want a firm, meaty green olive that holds its shape and keeps a bit of bite. A cracked green Picholine, a Nocellara del Belice, or a plain firm Spanish Manzanilla all work. What you do not want is a tired olive from a supermarket tub that tastes only of salt. Rinse whatever you use to knock back the harshest brine, then taste one — if it is pleasant to eat on its own, it will be good in the pan.

Getting the fish right

Tuna is lean and turns dry and chalky the moment it is overcooked. The trick here is a quick, hot sear to colour the outside, then a gentle spell in the oven under the sauce, which keeps it moist. Cut the steaks a good three-quarters of an inch thick so they do not cook through in the searing. If good tuna is dear or out of season, swordfish, a firm white fish or even chicken thighs take to the same sauce happily — the olive-tomato base is the constant.

The sauce, and a word on the oil

Soften onion and celery slowly, add puréed tomatoes and a pinch of dried chilli, and let it cook down until it is thick enough to sit on a spoon before the olives go in. Use an ordinary decent olive oil for the cooking; save your good extra virgin for a raw thread over the finished plate, where its aroma is not cooked away. Season late — olives are salty, and a heavy hand early will leave you no room to correct.

Green olive	Character	How it behaves baked
Picholine	Firm, nutty, slightly bitter	Holds shape; classic choice
Nocellara del Belice	Buttery, meaty, mild	Stays plump, gives savoury depth
Manzanilla	Firm, almondy	Reliable everyday olive for cooking
Soft black-brine olive	Wrinkled, sweet	Turns to mush — keep for the table

Method, briefly

1. Sear seasoned tuna steaks 2–3 minutes a side; lift into a baking dish.
2. Soften onion and celery in the same pan; add puréed tomatoes and a pinch of chilli.
3. Simmer 15 minutes until thick, then stir in a good handful of pitted green olives.
4. Spoon over the fish, cover, and bake at a moderate heat about 30 minutes.
5. Rest, then finish with a raw thread of extra virgin and chopped parsley.

• Rinse and taste your olives before they go in — brine varies wildly.
• Sear, then bake gently so the tuna stays moist, not chalky.
• Salt last: the olives are already doing that job.
• Cook with ordinary oil, finish with the good stuff raw off the heat.

Baked tuna with green olives: common questions

Which green olives are best for this dish?

Firm, meaty ones that hold their shape — Picholine, Nocellara del Belice or a good Manzanilla. Avoid soft, sweet olives, which collapse into the sauce.

Should I use pitted or whole olives?

Pitted is easier to eat, but whole olives keep a touch more flavour. If you use whole ones, warn your guests about the stones.

My tuna comes out dry — what am I doing wrong?

Tuna is very lean. Sear it quickly, then bake gently under the sauce, and pull it out as soon as it is just cooked through. Thicker steaks are more forgiving.

Can I make it without fresh tuna?

Yes. Swordfish, a firm white fish or chicken thighs all work with the same tomato-and-olive sauce.

Do I need to add salt?

Very little, and only at the end. Green olives are salty, so taste the sauce before reaching for the salt.

A house version of a classic northern-Mediterranean baked-fish dish; no third-party recipe reproduced.