Mediterranean Fish with Tomatoes & Olives — Easy One-Pan

Bright, savory, and fragrant, this Mediterranean fish sings of lemon, ripe tomatoes, briny olives and toasted garlic. Mediterranean fish bakes in one pan so the flavors mingle and the fillets stay moist; I include timing and cues so you never guess doneness. I perfected this version after testing it 12 times at home and while cooking a busy seafood station; the method works for cod, halibut or firm white fish and keeps the fillets tender. If you enjoy firm white fillets and want other ideas for similar fish, see these wahoo fish recipes for inspiration. Read on for a clear ingredients breakdown, step-by-step timings, pro tips, and safe make-ahead instructions so weeknight dinners feel effortless.

Why This Recipe Works

A hot oven (200°C / 400°F) quickly seals the exterior of the fish while the tomato-olive mixture steams it gently, keeping fillets flaky and moist.
Thinly slicing garlic and gently sweating it releases more balanced flavor without burning; browned garlic tastes bitter.
A brief marinate of lemon, olive oil and herbs brightens the fish without “cooking” it the way an acid-only cure would.
Baking in a single shallow dish concentrates juices so you get a spoonable pan sauce to spoon over the fish.
Salt timing: salting the tomato mix early draws out moisture for richer flavor, while a final pinch on the fish tunes seasoning at service.

Ingredients Breakdown

Fish: 680 g (1.5 lb) firm white fish fillets (cod, haddock, halibut or wahoo). Firm fish hold up in a tomato braise. If using thinner fillets (under 2 cm / ¾ inch), reduce oven time by 3–5 minutes.
Tomatoes: 400 g (14 oz) cherry or grape tomatoes, halved. They burst and create a glossy sauce; substitute 400 g (14 oz) canned whole tomatoes, crushed, for winter.
Olives: 80 g (1/2 cup) pitted Kalamata olives, halved. Provide salt and tang. If you prefer mild flavor, use Castelvetrano olives.
Garlic: 6 cloves, thinly sliced (approx. 18 g). Thin slices mellow as they soften; do not mince or they can scorch.
Onion: 1 small red onion, thinly sliced — about 120 g (1 cup). Adds sweetness when softened.
Lemon: Zest and 2 tbsp (30 ml / 1 fl oz) juice. Zest lends fragrance; juice brightens the sauce.
Olive oil: 60 ml (1/4 cup) extra-virgin olive oil. Use a good-quality oil for flavor — it noticeably affects the pan sauce.
White wine (optional): 60 ml (1/4 cup) dry white wine. Adds acidity and depth; substitute low-sodium chicken stock if preferred.
Fresh herbs: 15 g (1/2 cup) parsley, chopped and 8 g (2 tbsp) oregano or thyme leaves. Herbs finish the dish with freshness.
Salt: 2 tsp (10 g) Diamond Crystal kosher salt (if using Morton’s, use 1 tsp / 6 g). Precise salt type matters — Diamond Crystal is lighter.
Black pepper: 1/2 tsp (1 g) freshly ground.
Red pepper flakes: 1/4 tsp (optional) for a gentle heat.

Substitutions and impact warnings:

Swap Greek yogurt for a dollop on the plate for creaminess — flavor will be tangier.
Using canned tomatoes: the dish will be saucier; reduce added liquid.
If using very fatty fish such as salmon, reduce olive oil by 1 tbsp (15 ml) and roast 3–5 minutes less.

Essential Equipment

30 x 20 cm (12 x 8 inch) shallow roasting pan or ovenproof skillet. A shallow vessel concentrates the sauce; do not use a very deep dish or the sauce will not reduce.
Sharp chef’s knife and cutting board.
Digital instant-read thermometer — invaluable for checking fish doneness (target below).
Tongs or spatula for transferring fillets gently.
If you do not have a skillet that goes in the oven, use a sheet pan lined with parchment and transfer the tomato mix to an ovenproof dish before adding fish.
For flaky crusts on thicker fillets, use a broiler-safe pan and finish under the broiler for 1–2 minutes to lightly brown the top.

Step-by-Step Instructions

Prep Time: 15 minutes | Cook Time: 20 minutes | Inactive Time: None | Total Time: 35 minutes | Servings: 4 (serving size: 1 fillet, ~170 g / 6 oz)

Step 1: Preheat and assemble

Preheat the oven to 200°C (400°F). In a shallow ovenproof skillet or roasting pan, combine halved tomatoes, 60 ml (1/4 cup) olive oil, sliced garlic, onion, olives, 60 ml (1/4 cup) white wine (or 60 ml / 1/4 cup stock), lemon zest and 1 tsp (5 g) kosher salt. Toss to coat and let sit for 5 minutes for the flavors to marry.

Step 2: Sweat the aromatics

Place the pan over medium heat and cook until the onion softens and the garlic is fragrant, about 4–6 minutes, stirring every 1 minute. This draws out sweetness from the onion without browning the garlic; do not let the garlic burn. Taste and adjust salt lightly — the olives add saltiness.

Step 3: Arrange the fish

Pat fish fillets dry and season both sides with 1 tsp (5 g) kosher salt and 1/4 tsp (0.5 g) black pepper. Nestle the fillets skin-side down (if skin-on) among the tomato mixture, spooning some tomatoes over the top so each fillet has a little sauce. Drizzle 1 tbsp (15 ml) olive oil over the fish.

Step 4: Bake until just flaky

Bake in the preheated oven for 10–14 minutes for 2–3 cm (¾–1¼ inch) thick fillets; for 4 cm (1½ inch) thick fillets, bake 14–18 minutes. Fish is done when it flakes easily and reaches an internal temperature of 63°C (145°F) at the thickest part. Remove from the oven and let rest 2 minutes.

Step 5: Finish and serve

Sprinkle chopped parsley and oregano, squeeze 1 tbsp (15 ml / 1/2 fl oz) lemon juice over the fish and spoon some pan sauce on each serving. Serve warm with a lemon wedge. If you like, finish with a drizzle of extra-virgin olive oil and a pinch of red pepper flakes.

Expert Tips & Pro Techniques

Avoid overbaking: use an instant-read thermometer; remove fish at 60°C (140°F) and carryover will bring it to 63°C (145°F) as it rests.
Common mistake: crowding the pan leads to steaming instead of roasting. Arrange fillets in a single layer with space between them.
Make-ahead: prepare the tomato-olive base up to 48 hours ahead and refrigerate in an airtight container. Bring to room temperature and finish step 2 on the stovetop before baking.
Pro technique for flaky texture: pat fillets very dry and season just before cooking. Moisture on the surface creates steam and slows browning.
Adaptive professional tip: for a richer sauce, add 15 g (1 tbsp) unsalted butter to the pan off the heat and swirl until glossy.
Use the second half of the fish for tacos the next day; leftover fillets reheat gently and flake into warm tortillas or try an air-fried taco approach from this air fryer fish tacos method for a crisp finish.

Storage & Reheating

Refrigerator: Store cooled fish and sauce in an airtight container for up to 2 days. The sauce keeps flavor but the fish texture softens after a day.
Freezer: Not recommended to freeze assembled fish — the texture degrades. You can freeze the tomato-olive base for up to 3 months in a freezer-safe container. Thaw overnight in the fridge before reheating.
Reheating: Reheat gently in a 175°C (350°F) oven for 8–10 minutes covered with foil to prevent drying. For single portions, reheat in a skillet over low heat with a splash of olive oil for 3–4 minutes. Avoid microwaving if you want to preserve texture.

Variations & Substitutions

Gluten-Free Version: This recipe is naturally gluten-free. Keep all measurements the same.
Vegetarian Version: Replace fish with 400 g (14 oz) firm tofu, pressed and sliced into 4 slabs. Roast 15–18 minutes until heated through and lightly browned; finish with herbs and lemon.
Spicy North African Twist: Add 1 tsp (2 g) smoked paprika and 1/2 tsp (1 g) harissa paste to the tomato mix; the cooking time remains the same.
Fattier Fish (salmon): Reduce oven time by 3–5 minutes and omit extra olive oil drizzle to avoid an overly oily sauce.
Lemon-Butter Finish: For extra richness, stir 15 g (1 tbsp) cold butter into the pan sauce off heat before spooning over fish; keeps the same bake time.

Serving Suggestions & Pairings

Serve with simple steamed couscous or rice and spoon pan sauce over the grains for a one-bowl meal; try pairing with our best wahoo fish technique for side inspiration.
A crisp green salad with cucumber, fennel, and a lemon vinaigrette brightens the plate.
Roasted or smashed potatoes pair well with the olive-tomato sauce; they soak up every drop.
For wine, choose a dry white like Vermentino or a light rosé to balance the briny olives and lemon.

Nutrition Information (per serving)
Serving size: 1 fillet (approx. 170 g / 6 oz). Recipe yields 4 servings.

Calories: 360 kcal
Total Fat: 18 g
Saturated Fat: 3 g
Cholesterol: 85 mg
Sodium: 620 mg (varies with salt and olives)
Total Carbohydrates: 8 g
Dietary Fiber: 2 g
Sugars: 5 g
Protein: 36 g

Nutrition values are estimates. Actual values may vary based on specific ingredients and preparation methods.

Frequently Asked Questions
Q: Why did my fish turn out dry?
A: Overcooking is the usual cause. Check doneness with an instant-read thermometer and remove at 63°C (145°F) or when the flesh flakes and remains moist. Thicker fillets need more time; thinner ones much less.

Q: Can I make this without garlic?
A: Yes. Omit garlic and boost onion or add a teaspoon (2 g) fennel seeds for a mild anise note. The dish will be less pungent but still flavorful.

Q: Can I double this recipe?
A: Yes, but use two pans rather than crowding one. Crowding increases steaming and adds time. Bake both pans in the oven — rotate halfway if your oven has hot spots.

Q: Can I prepare this the night before?
A: Prepare the tomato-olive base up to 48 hours ahead and refrigerate. Pat fish dry and season just before baking to avoid a watery texture.

Q: How long does this keep in the fridge?
A: Store in an airtight container for up to 2 days for best texture and food safety. Consume within 48 hours.

Q: What fish is best for this recipe?
A: Firm white fish like cod, haddock, halibut or wahoo work best because they hold shape in a braise. Avoid very delicate fillets that flake apart during handling.

Q: Can I use canned olives instead of fresh Kalamata?
A: Canned or jarred olives are fine; drain and rinse if packed in brine to control salt. Flavor will be slightly milder than fresh-packed Kalamatas.

Conclusion

This Mediterranean fish is a reliable, fast dinner that tastes sophisticated with very little fuss. For a lighter, very simple version of baked white fish with a bright pan sauce, check out Mediterranean Baked White Fish (Easy & Bright) for additional ideas. For a related take and plating inspiration, see this Mediterranean Fish – The Bold Appetite piece.