Step 1

Pat the cod fillets very dry. Season both sides with salt and pepper.

Step 2

Heat the oil a 10-inch or similar cast-iron or heavy-bottom skillet over medium-high heat. Once the oil is hot and shiny (but not yet smoking), gently lower the fish into the oil, moving away from your body with your motion in case the oil splatters. Lower the heat to medium.

Step 3

Let the fish cook undisturbed on the first side for 2 to 3 minutes, until the underside is nicely golden.

Step 4

Gently flip the cod over. A flexible, thin metal spatula (such as a fish spatula) works best. The cod might stick a bit at first, but work gently and firmly and you'll get it. Place the butter in the pan. With a spoon, spread the pat around the fish. Tilt the pan away from you so that the butter pools, then baste the fish with the butter a few times.

Step 5

Continue cooking on the other side until the fish is opaque, flakes easily with a fork, and reaches 145 degrees F on an instant read thermometer, about 2 additional minutes.

Step 6

Sprinkle with fresh herbs and squeeze the lemon over the top. Enjoy immediately, with an extra squeeze of lemon if desired.