Remove damaged outer leaves from the sprouts, cut off the stalks, cut a cross in the base of the sprouts and wash them.

Bring the water and a little salt to the boil in a large saucepan, tip in the sprouts, cover the pan and simmer gently for 15 minutes.

Slice the sausages. Drain the sprouts, reserving 150 ml (1/4 pint) of the cooking water. Heat half the butter in a saucepan, sprinkle in the flour and cook until golden stirring continuously.

Gradually stir in the hot sprout water, add the milk and simmer for 5 minutes, stirring continuously.

Remove the sauce from the heat and stir in the sugar, nutmeg, salt to taste and egg.

Arrange the sprouts and sausage in a buttered ovenproof dish and cover them with the sauce. Sprinkle with the parsley and cheese and dot with the remaining butter.

Brown in a hot oven (220°C, 425°F, gas 7) for about 15 minutes.