Baked Halibut Tomato Basil

I discovered this halibut recipe on a quiet Tuesday evening when my neighbor dropped off a beautiful fillet from her fishing trip, and I had nothing but tomatoes from the garden and a handful of basil on the windowsill. The simplicity of it struck me immediately—no fancy techniques, just honest ingredients that let the fish speak for itself. Twenty minutes later, the kitchen smelled like the Mediterranean coast, and I realized I'd stumbled onto something I'd make again and again.

I made this for my sister the first time she visited after moving away, and watching her face when she tasted the combination of buttery halibut with that sharp, herbaceous relish made me understand why some meals stick with you. She asked for the recipe before dessert even arrived, and now it's become our thing—whenever we're both in town, this is what we cook together.

Ingredients

• Halibut fillets (4, about 170g each): Choose fillets that are roughly the same thickness so they cook evenly; if one is noticeably thinner, it'll dry out while the thicker one is still cooking.
• Olive oil: Use regular olive oil for the fish and reserve extra virgin for the relish where its flavor actually shines.
• Sea salt and black pepper: Don't skip seasoning the fish itself—it's your only chance to flavor the fish directly.
• Lemon slices: These aren't just garnish; they release moisture that keeps the fish from drying out as it bakes.
• Cherry tomatoes (2 cups, quartered): Their sweetness balances the brightness of everything else, and they're sturdy enough not to turn to mush.
• Fresh basil (1/4 cup, chopped): Add this at the last moment so it stays vibrant; old basil tastes like dried grass.
• Red onion (2 tbsp, finely diced): The bite of raw onion against soft fish is exactly right, but keep the pieces small so they don't overpower.
• Garlic clove (1, minced): One clove is plenty—you want it as a whisper, not a shout.
• Capers (1 tbsp, drained): These little salty pops tie everything together and prevent the relish from feeling one-note.
• Extra virgin olive oil (2 tbsp): This is where quality matters; use something you actually taste and enjoy.
• Balsamic vinegar (1 tbsp): Just enough to add depth without turning it into a vinegary mess.

Instructions

Heat the oven and prep your sheet:

Preheat to 200°C (400°F) and line a baking sheet with parchment paper or lightly oil it. This step takes ninety seconds but prevents the fish from sticking and makes cleanup effortless.

Dry and season the halibut:

Pat each fillet thoroughly with paper towels until the surface feels dry to the touch—this is what lets the edges get just slightly golden. Brush both sides with olive oil and season generously with salt and pepper.

Arrange and top with lemon:

Place the fillets on the sheet and lay lemon slices across the top of each one. The lemon will soften into the fish as it bakes and add subtle flavor without any acidic bite.

Bake until just cooked through:

Bake for 15 to 18 minutes depending on fillet thickness; the fish is done when it's opaque throughout and flakes easily with a fork. Overcooked halibut turns grainy, so start checking at the 14-minute mark.

Make the relish while fish bakes:

In a medium bowl, gently toss together the tomatoes, basil, red onion, garlic, capers, extra virgin olive oil, balsamic vinegar, salt, and pepper. Taste it and adjust the seasoning; this is your only chance to balance the flavors.

Plate and serve:

Transfer each fillet to a plate and spoon the relish generously over the top, letting some of the juices pool underneath. A small handful of extra basil on top adds a beautiful finish and a fresh taste.

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There's a moment when you pull that halibut from the oven and the kitchen fills with the scent of lemon and olive oil that reminds you why cooking for people you care about matters. That's when this becomes more than dinner—it's an offering.

Why This Fish Works

Halibut has a mild, slightly sweet flavor that doesn't compete with the brightness of the relish, and its firm texture holds up beautifully in the oven without turning into flakes before it reaches your plate. If halibut isn't available or feels too expensive on a given week, cod, sea bass, or any firm white fish will work just as well—just stick with fillets roughly the same size so they cook evenly.

Building the Relish Right

The beauty of this relish is that it's structured but not rigid; I've learned that the tomatoes should be cut large enough that they don't dissolve into liquid but small enough that each bite feels considered. The capers are key—they provide a salty, briny contrast that keeps everything from tasting too soft or sweet, and the basil has to go in at the very end so it stays green and fresh tasting rather than turning dark and medicinal.

What Makes It Special

This dish walks a careful line between feeling elegant and being genuinely easy, which is why it's become my go-to when I want to cook something that feels intentional without spending hours in the kitchen. The Mediterranean flavors make it feel like a treat, but the short cook time means you can have it on the table on a weeknight without stress. If you want to round it out into a fuller meal, roasted potatoes or steamed green beans on the side are perfect, or serve it with a cold glass of Sauvignon Blanc or Pinot Grigio to match the brightness of those flavors.

• Diced avocado stirred into the relish just before serving adds unexpected creaminess without weighing it down.
• If you can't find fresh basil, use parsley instead—it won't have the same subtle anise note, but it will still be delicious.
• Make the relish up to two hours ahead and keep it at room temperature; it actually develops better flavor as it sits.

Save

This halibut has become the recipe I reach for when I want to prove to myself that simple food, cooked with attention, is enough. Make it for someone you want to impress or make it for yourself on a night when you deserve something that tastes this good.

Recipe FAQs

→ What is the best way to bake halibut fillets?

Preheat the oven to 200°C (400°F), place seasoned halibut fillets on a lined baking sheet, and bake for 15–18 minutes until opaque and flaky.

→ Can other fish be used instead of halibut?

Yes, firm white fish like cod or sea bass work well as substitutes in this preparation.

→ How should the tomato and basil relish be prepared?

Combine quartered cherry tomatoes, chopped basil, diced red onion, minced garlic, capers, olive oil, balsamic vinegar, salt, and pepper, and mix gently.

→ What are some serving suggestions for this dish?

Pair with roasted potatoes, steamed green beans, or a crisp white wine like Sauvignon Blanc or Pinot Grigio.

→ Can this dish accommodate dietary restrictions?

It is naturally gluten-free and low carb, suitable for those dietary preferences.