Preparation of fish Fillet grouper to a thickness of about 5 to 6 cm. Then wash fillets well and then place them in a colander to drain. We salt the fillets using coarsely ground salt. Our fish must remain in salt for 3 to 4 hours at least, or it can be prepared from the previous day. In the latter case, we keep the grouper in the refrigerator (in a colander) placing a container (usually a pan)underneath to catch and contain the liquids. Attention! Do not remove the skin of the grouper. Onion juice Peel and wash 4 onions. Cut them into large pieces. Boil them over a hot fire in plenty of water for at least one hour. Once this mixture has cooled, pulp the onions and their liquid using a juicer or a blender, this will give you a thick liquid. This is onion juice. In the old days of course we mashed the boiled onions with a fork. Cooking Place the grouper fillets in the pan in such a way that the bottom of the pan is completely covered. It is good to place the head of the grouper alongside the fillets, which makes the fish tastier and thickens the sauce better. Then place the pan on a hot stove. After you have placed the fish in the pan, pour the onion juice over it, which must be cold, and add cold water until the fish is well covered, but no more, or the broth will not thicken. When it starts boiling, skim it with a slotted spoon and add the onions which we have cut into very thin slices, the garlic (whole cloves), and at the same time the olive oil. Add the peppercorns and let the fish boil over high heat for about an hour. Then lower the heat by half and shake the pan once in a while (without stirring the pieces with a spoon) so that the fish does not stick. Gradually, the sauce reduces and starts thickening. Be careful, I remind you, especially as the end approaches, not to let the fish stick to the pan. Pour the lemon juice into the pan 30 seconds before you remove the food from the heat. As soon as you take it off the heat, add the ground pepper and the chopped parsley if you wish, and cover the pan with its lid for about 30 minutes. The food is always served using a flat spoon (so as not to break the fish) in a platter or directly onto the plates and then the sauce is poured carefully over the fish. It is eaten warm because when it cools the sauce thickens.