Baked Halibut with Tomato and Basil

That bright Thursday last May, my kitchen filled with the scent of basil as I stood over the cutting board, trying to recreate something Id tasted at a tiny seaside restaurant in Barcelona the summer before. The waiter had simply called it fish with tomatoes, but the memory of those sweet acidic juices cutting through the buttery halibut stayed with me across an ocean. My roommate poked her head in, drawn by the balsamic vinegar, and asked what smelled like sunshine.

I made this for my parents anniversary dinner that same month, nervously checking the oven door every three minutes like a peeking Tom. My dad who usually tolerates fish at best went back for seconds and actually asked if there was any left for lunch the next day. Seeing someone change their mind about seafood because of one perfectly cooked piece of fish felt like a tiny victory.

Ingredients

• Halibut fillets: This fish is worth the extra cost because its meaty texture holds up beautifully to baking and its mild flavor lets the relish really shine
• Olive oil: Use two tablespoons for brushing the fish but splurge on the extra virgin stuff for the relish where its fruity notes really matter
• Lemon: Both zest and juice go into the fish marinade, adding brightness that cuts through the richness
• Cherry tomatoes: Quartered tomatoes release just enough juice to create a sauce without making the relish watery and their sweetness balances the balsamic
• Fresh basil: Nothing compares to the real thing here and chopping it right before serving keeps those aromatic oils intact
• Red onion: Finely diced so you get little bursts of sharpness without overwhelming the delicate fish
• Balsamic vinegar: Just one tablespoon adds depth and a subtle sweetness that ties everything together
• Garlic: One minced clove is plenty since it will mellow slightly while the relish sits

Instructions

Get your oven ready:

Preheat to 400F and line a baking sheet with parchment paper for effortless cleanup later

Prep the fish:

Pat each halibut fillet completely dry with paper towels and arrange them on the prepared baking sheet with some space between each piece

Make the lemon mixture:

Whisk together the olive oil, lemon zest, lemon juice, half teaspoon salt, and quarter teaspoon pepper in a small bowl until combined

Season both sides:

Brush the lemon mixture generously over both sides of each fillet using a pastry brush, making sure every bit of fish gets coated

Bake until perfect:

Slide the sheet into the oven for fifteen to twenty minutes until the fish turns opaque throughout and flakes easily when tested with a fork

Build the relish:

While the fish cooks, toss quartered cherry tomatoes, diced red onion, chopped basil, extra virgin olive oil, balsamic vinegar, minced garlic, quarter teaspoon salt, and eighth teaspoon pepper in a medium bowl

Let flavors marry:

Set the relish aside at room temperature for ten minutes, giving the tomatoes time to release their juices and the flavors a chance to blend

Plate and serve:

Transfer each baked fillet to a plate and spoon that beautiful tomato basil mixture generously over the top, adding extra basil or lemon wedges if you are feeling fancy

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This recipe has become my go to for dinner parties because I can prep everything ahead and assemble it right when people walk through the door. Last week my friend who swore she hated fish actually asked for the recipe before she even finished her plate. Thats the kind of cooking win that keeps you coming back to the kitchen.

Choosing the Best Fish

Look for halibut that looks translucent and almost pearlescent rather than dull or matte. If your fish counter is out, cod and sea bass work beautifully here though halibuts firm texture really is ideal for this preparation. Trust your nose, fresh fish should smell like the ocean not like fish.

Making It Your Own

Sometimes I add a pinch of red pepper flakes to the relish when I want a little warmth, and in late summer when tomatoes are at their peak, heirloom cherry tomatoes make this dish absolutely sing. The recipe is forgiving enough that you can play around while still getting reliably delicious results.

What to Serve Alongside

Something green and crisp like steamed asparagus or roasted broccolini balances the richness of the fish perfectly. A chilled glass of Sauvignon Blanc cuts through the olive oil while letting the mild halibut shine, and warm roasted new potatoes make this feel like a complete meal.

• Keep the relish cold until the last second for that gorgeous temperature contrast
• Extra basil never hurt anyone, do not be shy with the garnish
• Lemon wedges on the side let guests adjust the acidity to their taste

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Heres to many warm evenings spent around the table with good food and better company. Enjoy every bite.

Recipe FAQs

→ How do I know when the halibut is done?

The halibut is ready when it turns opaque throughout and flakes easily with a fork. This typically takes 15-20 minutes at 400°F. Thicker fillets may need a few extra minutes.

→ Can I prepare the tomato basil relish ahead of time?

Yes, the relish can be made up to 2 hours in advance and kept at room temperature. This actually allows the flavors to meld together better for a more vibrant taste.

→ What other fish work well with this preparation?

Cod, sea bass, or mahi-mahi make excellent substitutes. Adjust cooking time slightly based on thickness—thinner fillets may cook faster, while thicker ones may need extra minutes.

→ What sides pair best with this dish?

Steamed asparagus, roasted new potatoes, or a light quinoa salad complement beautifully. A crisp Sauvignon Blanc or Pinot Grigio balances the fresh flavors perfectly.

→ Can I grill the halibut instead of baking?

Absolutely. Grill over medium-high heat for 4-5 minutes per side, brushing with the lemon-olive oil mixture. The relish works equally well with grilled halibut.

→ Is this dish suitable for meal prep?

The halibut is best enjoyed fresh but can be refrigerated for up to 2 days. Store the relish separately and add just before serving to maintain texture and freshness.