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Fish Fillets with Tomatoes, Squash, and Basil

This elegant white fish with summer squash and basil is a wonderful example of heart-healthy cooking that doesn't compromise on flavour. By steaming the fish in individual parchment parcels, you lock in the delicate juices of the cod or halibut alongside sweet cherry tomatoes and seasonal squash. The addition of dry white wine and extra-virgin olive oil creates a light, fragrant sauce that perfectly complements the tender vegetables and flaky fish.

Perfect for a quick midweek dinner or a light weekend lunch, these parcels can be prepared up to four hours in advance and kept in the fridge. Whether you choose to bake them in the oven or cook them over a grill for a smoky finish, this dish is a nutritious, low-effort meal that brings a fresh, Mediterranean feel to your table.

Continue reading below

Ingredients for Fish Fillets with Tomatoes, Squash, and Basil

  • 475ml very thinly sliced assorted summer squash (such as courgette, yellow crookneck, and pattypan)

  • 30g thinly sliced shallots

  • 1/4 cup thinly sliced fresh basil, divided, plus 1/4 cup basil leaves

  • 20 cherry tomatoes, halved

  • 60ml dry white wine

  • 4 tablespoons extra-virgin olive oil, divided

  • Kosher salt, freshly ground pepper

  • 110g skinless white flaky fish fillets (such as Atlantic cod or halibut)

How to make Fish Fillets with Tomatoes, Squash, and Basil

Place four 14x12" sheets of parchment paper, or heavy-duty foil if grilling, on a work surface. Divide squash among parchment sheets, arranging on one side of sheet in thin layers. Sprinkle shallots and sliced basil over, dividing equally. Scatter tomato halves around squash. Drizzle each packet with 1 tablespoon wine and 1/2 tablespoons oil (add 1/2 tablespoons water to each if grilling). Season with salt and pepper. Place a fish fillet atop each portion. Season with salt and pepper; drizzle 1/2 tablespoons oil over each.

Fold parchment over mixture and crimp edges tightly to form a sealed packet. DO AHEAD: Can be made 4 hours ahead. Chill. Let stand at room temperature for 15 minutes before continuing.

Preheat oven to 204°C. Place packets in a single layer on a large rimmed baking sheet. Alternatively, build a medium fire in a charcoal grill, or heat a gas grill to medium-high. Bake or grill fish until just cooked through (a toothpick poked through the parchment will slide through fish easily), about 10 minutes. Carefully cut open packets (steam will escape). Garnish with basil leaves.

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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