Arpagyongy Kremleves (Cream Of Pearl Barley Soup)

1. Cook bones and vegetables in 1 1/2 quarts water for about 2 hours.
2. Keep skimming the broth to remove scum.
3. Straini.
4. Add enough water to bring the amount to 1 1/2 quarts again.
5. Add barley to the broth and cook until it is soft.
6. Make a roux with butter and flour.
7. Cook the roux over low heat, stirring constantly, but do not let it become dark.
8. This should be a light roux.
9. Stiri 1/3 cup cold water and 1/3 cup cold milk into the roux and whip until smooth.
10. Pour into soup and simmer it for 10 minutes.
11. Pureei the soup in a blender or through a sieve.
12. Adjust the salt to taste.
13. Mixi cream with egg yolk and put it in a soup tureen.
14. Just before serving, pour hot creamed soup over the yolk and cream mixture.