Pat cod fish dry with paper towel and season well with salt and pepper.
In a large skillet or frying pan, heat the olive oil over medium high heat.
Reduce heat to medium and place fillets in the pan skinned side down. Gently press on each fillet a spatula for 5 seconds to ensure good contact with the pan. Cook the fillets without moving them, until the underside is golden brown, about 4 minutes.
Flip the cod cook a further 3-4 minutes, basting with the butter (the butter will brown). When the fish is fully cooked reaching an internal temperature of 145°F/62°C, remove from the pan and set aside.
Add the garlic to the butter in the pan and cook for about 30 seconds. Add the chopped parsley and lemon juice. Taste for seasoning and add salt as needed. Serve over the cod.
Buy fillets that are uniform in size to ensure even cooking times.
Always ensure the pan is hot before searing the cod, it ensure the flavor is sealed in and prevents it from breaking apart.
Take the fish out of the pan to cool, if left in the pan the residual heat will keep cooking the fish, resulting in a tough texture.
To make sure the cod is cooked thoroughly, insert a fork into the thickest part of the fillet. Twist gently at an angle (the fish should flake apart easily if cooked properly). The fish should have an opaque appearance rather than a translucent one, once it’s cooked. If you have a thermometer the temperature should be 145°F/63°C.