To make the marinade for pan-seared halibut, add 6 tablespoons of olive oil, 3 cloves of garlic, 1 teaspoon of dried basil, 2 tablespoons of lemon juice, 1 teaspoon of salt, and 1 teaspoon of pepper to the bag. Thoroughly mix everything together until it’s uniform.
Carefully place the halibut fillets inside the bag with the marinade. Seal the bag and put it in the fridge.
Let the halibut marinate for at least, 30 minutes. The longer you leave it there the better it will taste. However, do not marinate the fish for more than two hours. This can start to “cook” the fish and will result in a poor texture.
Heat the skillet over high heat. Once the skillet is hot, drizzle it with olive oil. Swirl the pan so the oil coats the surface completely in a thin layer.
Remove the fish from the bag with the marinade and discard the excess marinade. Use a fish spatula to carefully place the fish in the hot skillet.
Cook on the first side for three minutes, then flip and cook for another three minutes on the other side. Season each side with salt and pepper as you go.
Reduce the heat to medium. Now cook for another three minutes per side. This lower heat step allows the fish to cook through in the center.
Check the thickest part of one of the fillets with a fork. If it flakes easily and looks opaque in the center, it’s time to eat! Otherwise, continue cooking for a minute or two.