Scandinavian Mackerel

3 tablespoons cider vinegar
300 ml/1/2 pint water
1 onion, peeled and sliced
1 bay leaf
1 parsley sprig
I thyme sprig
6 peppercorns
V2 teaspoon salt
4 mackerel. cleaned
Sauce:
150 ml/1/2 pint plain low-fat yogurt
I tablespoon French mustard
I teaspoon Muscovado sugar
I tablespoon cider vinegar
I tablespoon chopped fennel

Put the vinegar, water, onion, herbs, peppercorns and salt in a pan. Bring to the boil and simmer for 20 minutes.

Place the mackerel in a shallow ovenproof dish and pour over the infused liquid. Cover and cook in a preheated moderate oven (180`C/350 °F, Gas Mark 4) for 20 to 25 minutes. Transfer the fish to a warmed serving ads and keep hot.

Put all the sauce ingredients in a small bowl and place over a pan of simmering water. Stir until blended and heated through. Pour the sauce over the fish and serve immediately.

SERVES 4