Heat the oil in a large frying-pan. Add the onion and garlic and fry until they are soft. Remove the pan from the heat and stir in the ground almonds, breadcrumbs, 3 tablespoons of parsley and the tomatoes. Return to the heat and cook for 5 minutes, or until the liquid has evaporated and the mixture is thick. Remove from the heat and set aside.

Preheat the oven to moderate 180°C (Gas Mark 4, 350°F).

Arrange the fish fillets, in one layer, in a large baking pan. Pour over the hot water and lemon juice and add the salt and bouquet garni. Cover with foil and place the tin in the oven. Poach for 8 to 12 minutes, or until the flesh flakes easily. Remove from the oven and transfer the fillets to a warmed serving dish. Keep hot while you prepare the sauce.

Strain and reserve 75 ml (3 fl oz) (3/8 cup) of the cooking liquid. Add it to the tomato and almond mixture in the frying-pan and stir well to blend. Set the pan over moderate heat and cook until the mixture is smooth, stirring constantly.

Pour the sauce over the fish and sprinkle over the flaked almonds and remaining parsley. Serve at once.