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Mahimahi with Onion, Capers, and Lemon

This Mediterranean-inspired mahimahi with onion, capers, and lemon is a vibrant and nutritious choice for anyone seeking a fresh, high-protein meal. The firm, mild flavour of the fish provides a perfect canvas for the salty punch of chopped capers and the bright acidity of fresh lemon juice. By caramelising the onions gently before finishing them with a touch of butter, you create a sophisticated sauce that feels indulgent while remaining light and wholesome.

As a diabetes-friendly main course, this dish focuses on lean protein and heart-healthy olive oil, making it a brilliant addition to a balanced weekly menu. The grilling method ensures the fish remains succulent with a beautifully crisp skin, providing a lovely textural contrast to the softened onions. Serve it alongside steamed seasonal greens or a crisp garden salad for a satisfying, low-carbohydrate dinner that is as simple to prepare as it is elegant to serve.

Continue reading below

Ingredients for Mahimahi with Onion, Capers, and Lemon

  • 3 tablespoons olive oil

  • 1 large onion, halved lengthwise, then thinly sliced crosswise

  • 3 tablespoons water

  • 1/2 teaspoons black pepper

  • 3 tablespoons unsalted butter

  • 45ml capers (in brine), rinsed, drained, and coarsely chopped

  • 40ml fresh lemon juice

  • 4 (170g) pieces mahimahi fillet (1 1/2 to 2 inches thick) with skin

  • 3/4 teaspoons salt

  • 2 tablespoons chopped fresh flat-leaf parsley

How to make Mahimahi with Onion, Capers, and Lemon

Heat 2 tablespoons oil in a 12-inch heavy skillet over moderately high heat until hot but not smoking, then sauté onion, stirring frequently, until golden, about 6 minutes. Stir in water and 1/4 teaspoons pepper and cook, stirring, until onion is softened, about 1 minute. Stir in butter until melted, then stir in capers and lemon juice. Remove from heat and keep warm, covered.

Preheat grill.

Pat fish dry, then brush all over with remaining tablespoon oil and sprinkle with salt and remaining 1/4 teaspoons pepper. Put fillets, skin sides down, on rack of a grill pan and grill about 5 inches from heat until just cooked through, 6 to 8 minutes.

Serve fish topped with onion mixture and sprinkled with parsley.

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.

  • 17 Jan 2026 | Originally published

    Authored by:

    UK recipe editors

    Peer reviewed by

    UK recipe editors
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