4 mackerel, halved and filleted
1 tablespoon oil
salt and pepper
juice of 1 lemon
25 g (1 oz) butter or margarine
25 g (1 oz) plain flour
300 ml (1/2 pint) milk
2 teaspoons mustard powder
1 teaspoon white wine vinegar
1 teaspoon honey
1 tablespoon chopped parsley
sprigs of flat-leaved parsley
1. Place the mackerel fillets on a sheet of greased foil and brush with the oil. Season generously with salt and pepper, sprinkle over the lemon juice. Fold the fillets into little parcels, wrap them securely in the foil.
2. Cook in a steamer for 20-25 minutes. Meanwhile, melt the butter or margarine over a gentle heat, add the flour, then gradually add the milk, stirring continuously. Bring the sauce to the boil, reduce the heat, add the remaining ingredients, season to taste and simmer for 2 minutes.
3. Unwrap the fish and transfer to a serving dish, reserving the cooking liquor. Keep the fish warm. Add the cooking liquor to the sauce and simmer for a further few minutes, then pour over the mackerel.
4. Garnish with parsley sprigs and halved slices of lemon and lime.
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