This is how I like my fried fish. The ideal degree of doneness is medium-rare, neither solidly opaque nor mostly translucent, but just at the point between these two states. It will be sweet, salty, moist, lightly crisped – no big crunch – and not greasy.
A lightly acid sauce on the side balances the equation. The traditional choices are agristada – a smooth, cooked lemon sauce (that so-called French treatment), ajada – raw garlic spread, mayonnaise, or vinagre – tomato-vinegar sauce with or without garlic.
Boneless, skinless fillets of fresh white fish – cod, scrod, hake, halibut, etc. They should be of uniform thickness
Flour for dredging – use flour that’s marked for frying, if you can find it, or hard wheat flour (bread flour). If you want to try chickpea, blend it with wheat flour.
Extra virgin olive oil – I live in Spain and olive oil is cheap. If yours is too precious to use up on a fish fry, blend it with a sunflower oil meant for frying.
A heavy-gauge frying pan or skillet
Tongs or a spatula, or both
1. If the fillets are very thick, cut them crosswise into pieces abut 2 inches wide. Wipe them with a damp paper towel, salt lightly on both sides and set aside for ten minutes. This step draws off moisture from inside the fish, which firms it up for frying.
2. Pour oil into the pan to a depth of about 1-1/2 inches. Heat the oil without letting it start to smoke. This is critical. If cooking oil smokes, it’s ruined. Don’t even bother trying to salvage it, just start over. You know by sight it’s getting too hot if it suddenly loses viscosity (it looks very thin). If that happens, immediately remove the pan from the heat source and lower the temperature. (Absent a thermometer and well before you’ve heated the oil too much, you can test the temperature by tossing in a little piece of bread. If it sizzles, floats and turns brown quickly, you’re on.)
3. Dredge the salted fish in flour and shake off any excess. Slip the fillets into the hot oil one piece at a time and without crowding. Crowding will trap moisture, lower the temperature, block the oil from circulating freely and prevent the fish from crisping. Fry in batches if you need to. As soon as you add the fish the oil should bubble up. Immediately reduce the flame to medium/medium-high. The oil needs to be kept hot enough to continue at a lively bubble, and the bubbling oil should at most just barely coat the exposed top of the fish (you’re pan frying, not deep frying).
As the fish cooks it will release vapor; remember to make sure that’s the only kind of smoke you’re seeing, and adjust the flame slightly up or down as needed, but don’t let the bubbling subside. When the fish has developed a golden crust on the bottom, turn it over to finish cooking on the other side. Turn the fish over only once. When golden on the second side, remove to a warm plate lined with paper towels and sprinkle lightly with salt while still hot.