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Oil-Poached Halibut with Tomatoes and Fennel

This elegant oil-poached halibut with tomatoes and fennel is a sophisticated yet simple way to prepare white fish. By gently simmering the halibut in extra-virgin olive oil infused with aromatics like orange zest and bay, the fish retains its delicate moisture and develops a buttery, flaky texture. The sweetness of the slow-cooked fennel and tomatoes provides a vibrant contrast to the savoury fish, making this a standout dish for a dinner party or a special weekend meal.

As a heart-healthy choice, this recipe relies on high-quality fats and fresh Mediterranean flavours rather than heavy sauces. It is wonderfully versatile and can be served either warm or at room temperature. For a complete meal, pair it with some steamed new potatoes or crusty sourdough bread to soak up the fragrant poaching oil.

Continue reading below

Ingredients for Oil-Poached Halibut with Tomatoes and Fennel

  • 8 garlic cloves, smashed and peeled

  • 3 medium fennel bulbs, trimmed, reserving some fronds for garnish, and bulbs (including core) cut lengthwise into 1/4-inch-thick slices

  • 675g small (1 1/2- to 2-inch) tomatoes (preferably Campari), halved

  • 1 teaspoon fennel seeds

  • 1 teaspoon sugar

  • 1 Turkish or 1/2 California bay leaf

  • 3 (3- by 1-inch) strips orange zest

  • 0.9L extra-virgin olive oil

  • 1 (1.1kg) piece skinless halibut fillet (about 1 1/2 inches thick)

  • a 5- to 6-quart heavy pot (at least 4 inches deep)

How to make Oil-Poached Halibut with Tomatoes and Fennel

Simmer garlic, fennel bulbs, tomatoes, fennel seeds, sugar, bay leaf, zest, and 1 teaspoon salt in oil, stirring occasionally, until vegetables are tender but still intact, 30 to 40 minutes.

While vegetables simmer, rub fish with 1 1/2 teaspoons salt and 1/2 teaspoons pepper and let stand 10 to 20 minutes.

Transfer vegetables to a bowl with a slotted spoon, then submerge fish in oil (if necessary, to lift level of oil, return vegetables to pot) and cover surface of oil with parchment paper. Cook fish over medium heat (without simmering) 5 minutes and remove from heat. Let fish cook from residual heat (still covered with parchment) until just cooked through, 10 to 15 minutes.

Carefully transfer fish to a platter using 2 metal spatulas. Discard bay leaf. Surround with vegetables. Drizzle with some of oil and sprinkle with chopped fronds. Serve warm or at room temperature.

Disclaimer

While every effort has been made to ensure the information is accurate and up to date, individual needs may vary and dietary requirements can differ based on personal health conditions. Always check food labels and allergen information before preparing or consuming any recipe. If you have specific health concerns, allergies, intolerances, or are following a medically prescribed diet, seek advice from your GP, pharmacist, or a registered dietitian before making significant changes to your diet or lifestyle.

Article history

The information on this page is peer reviewed by qualified clinicians.

  • 16 Jan 2026 | Originally published

    Authored by:

    UK recipe editors

    Peer reviewed by

    UK recipe editors
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