Make the sauce. Cook onion and garlic in 3 tablespoons olive oil until onion is nearly brown. Add hot peppers and tomatoes, and cook until liquid has evaporated. Put the mixture through a sieve to separate tomato skins and seeds. Season the sauce with salt and white pepper to taste.

Cover the bottom of an earthenware serving dish with a layer of sauce, and place the cod squares on top. Cover with the rest of the sauce and arrange the pimiento strips around the dish. Sprinkle with the parsley and dribble remaining 1 tablespoon olive oil over all. Put in a moderate oven (350 degrees F) for 10 minutes, or until everything is heated through, and serve at once.

Basic Preparation of Salt Cod
Salt cod must be soaked in fresh water before cooking. The duration of this period depends on the original cure; a heavily salted product may require up to 24 hours while a lightly cured cod fillet will be restored in half that time. Size is also a factor, but if the fish is hard as a board then it underwent a heavy cure. A lightly cured cod fillet is flexible due to its greater moisture content. Most cod fillets are too large to cook whole but they can be cut into large or small pieces, leaving the rib cage area around the belly intact if you plan to make a dish that requires cod gelatin, which is essential to the sauce in Bacalao Ligado. This part of the cod (as well as the head if you have salted your own and reserved it) provides a delicate gelatin suitable to a number of recipes.

After soaking pour off the water and cover the fish again with fresh cold water, then heat it gently on the stove. When the water begins to bubble, skim off the froth, reduce the heat, and poach for 15 to 20 minutes according to the thickness of the fish. Drain the cod and proceed.