The difference between a moist, buttery salmon fillet with a crunchy, crisp skin and an underwhelming steak whose texture is tough, dry and chalky can be a couple of minutes only. Pan-fried salmon demands very little skill and attention, however, and a steak that is about to overcook shows clearly visible signs of doing so.
Because salmon requires a short cooking time only, the searing needs to begin the moment the steak hits the pan. To this end, heat a heavy skillet, which will hold the heat and distribute it evenly, and add a dash of olive oil until it starts to shimmer. Pat the salmon steaks dry to stop them sticking to the pan and spitting in the oil, and to prevent any water from reducing the pan's temperature. Place the salmon steaks skin-side down in the pan. Even if you plan to remove the skin before serving, the skin and its layer of subcutaneous fat provide a crucial heat barrier between the pan and the more succulent flesh during cooking.
Once the salmon is in the pan, reduce the heat immediately so that the flesh retains its moisture while the fats and proteins break down. Fry for 4 to 5 minutes, depending on the thickness of the steak and type of salmon. Smaller sockeye fillets overcook easily; whereas thicker, fattier king salmon is more robust. Avoid moving the steak around as this will only break up the flakes, but do press down with a spatula to keep it in place as the skin contracts and curls, which can lead to uneven cooking. If albumen, a white frothy substance, starts to ooze from the fillet, remove the pan from the heat immediately, as the steak is overcooking and will have an insipid taste and dry texture. If cooking smaller salmon pieces, sauteing by tossing the fish in hot oil will give a uniform crispiness, but an additional sauce or seasoning will help retain moisture.
Slide the spatula underneath the fillet. If you find you have to wrestle it under, leave the fillet to cook a little longer. Flip the salmon steak and fry for an additional 3 minutes. The skin should be retracted and crispy, with a clear color gradient visible along the salmon flesh, from light to dark pink. Alternatively, some chefs choose to cook the steak through almost entirely with only the skin-side down, flipping it over at the last moment for a matter of seconds to give it a crisp finish. Serious Eats recommends inserting a kitchen thermometer to check that the internal temperature is as close to 120 degrees Fahrenheit as possible. The connective tissue starts to break down at 110 F, but allow the temperature to reach 125 F and the salmon will flake and start to take on a chalky texture.
A dry sear in a very hot skillet exploits the salmon's intrinsic fat content but minimizes the overall oiliness and calorie count. Simply sprinkle the steak with kosher salt, paprika and pepper, and cook as before, although the saltier skin is best discarded after cooking. Some cooks brush the steaks with a little oil or butter on both sides to guarantee the required level of crispiness. Blackened salmon produces the fullest-flavored crust. Brush the steaks with melted butter and then sprinkle with a dry rub incorporating paprika, chili, cayenne, garlic and onion powders, along with pepper and dried herbs such as thyme and oregano. Drizzling the steaks with melted butter during cooking will intensify the Southern-style flavors and seal in moisture.