French Oyster Soup

1 quart oysters
1 quart milk
1 slice onion
2 blades mace
1/3 cup flour
1/3 cup butter
2 egg yolks
salt and pepper

Clean oysters by pouring over ¾ cup cold water. Drain, reserve liquor, add oysters, slightly chopped, heat slowly to boiling point and let simmer 20 minutes; strain.

Scald milk with onion and mace. Make white sauce and add oyster liquor. Just before serving add egg yolks, slightly beaten.