• Make two or three diagonal cuts in the flesh on both sides of the fish. Sprinkle with salt and pepper and brush with oil or melted butter. Grease the grill rack and put the fish on it.
• Grill the herrings under a moderate heat, turning them once, for 10-15 minutes or until thoroughly cooked; test with a fork. Serve with mustard sauce.

Mustard Sauce

• Use for carrots, celery hearts, herring, mackerel, cheese, ham and bacon dishes.
• Makes 450 ml (3/4 pint)
• Melt the butter in a saucepan. Add the flour and cook over low heat, stirring, for 2 minutes.
• Remove from the heat and gradually stir in the milk. Return to the heat and bring to the boil slowly. Continue to cook, stirring until the sauce thickens. Simmer for a further 2-3 minutes.
• Blend the mustard powder with the vinegar and whisk into the sauce, season. Stir in the fresh cream (if using). Reheat but do not boil.