Serves 6

1 kg (2 lb) boned shoulder of lamb, trimmed and cubed

5 g (1 tsp) salt

10 g (1 tbsp) dried tarragon or 15 g (2 tbsp) fresh, chopped

600 ml (1 pt) water

1 medium onion, chopped

40 g (1 1/2 oz) butter or margarine

25 g (1 oz) flour

15 ml (1 tbsp) tarragon vinegar

1 egg yolk

150 ml (1/4 pt) sour cream

pepper

1. Put the lamb into a large pan with the salt, tarragon, water and onion.

2. Bring to the boil and then cover and simmer for about 1 hour, or until the meat is tender.

3. At this stage you might care to cool the lamb overnight and skim off the fat before continuing.

4. In a clean pan melt the butter and stir in the flour off the heat.

5. Add a little stock from the meat and stir it in well to make a smooth sauce.

6. Return this mixture to the meat and add the vinegar. Cook for 5 minutes.

7. Mix the egg yolk into the sour cream. Add several spoonsful of the hot liquid, a little at a time, and then return the mixture to the pan on a very gentle heat.

8. Stir well.

Variation Substitute dill for the tarragon if you prefer.