Fish Marinated in Herbed Olive Oil

A foundational Mediterranean fish technique, not really a specific recipe. Any firm fish fillet (swordfish, halibut, salmon, tuna, mahi mahi) marinates overnight submerged in olive oil perfumed with garlic, rosemary, oregano, and parsley. The oil protects the delicate flesh and infuses it with herbal flavor without ever touching the harsh side of acidic marinades.

Most marinades use lemon or vinegar, which start cooking fish almost immediately and turn the flesh mealy after a few hours. Olive oil does the opposite: it keeps fish tender, seasons it gently, and holds up to long refrigeration. Overnight is actually better than a few hours.

Wipe the excess oil before grilling, broiling, or baking. Salt just before cooking. Serve with lemon wedges so each eater can add their own citrus brightness. Save the leftover herbed oil in the fridge for the next batch; it gets more flavorful after being used.

Chef Tips

• Use a high-quality extra-virgin olive oil. It’s doing most of the flavor work here, so cheap oil shows through in the final taste.
• Pat the fish dry before cooking. Wet fish steams in the pan or on the grill instead of searing into that beautiful crust.
• Don’t salt the fish before or during the marinade. Salt draws moisture out and turns the flesh stringy; save it for right before cooking.
• Reuse the oil only for fresh seafood, as the directions specify. Never use it for raw poultry or meat.

Variations

• Add lemon zest (not juice) to the oil for floral citrus notes without acidic damage to the fish.
• Use tarragon or dill with salmon or trout in place of the rosemary-oregano combo.
• Swap fresh herbs for dried if that’s what you have. Use half the quantity since dried herbs are more concentrated.