a. 1/4 cups minced green onions (or yellow onions)
3 Tb butter
Cook the onions slowly in the butter in a covered saucepan for 5 to 10 mins., until tender and transluscent but not browned.
b. 3-4 packed cups fresh watercress leaves & tender stems, washed & dried
1/2 tsp salt
Stir in the watercress & salt, cover, and cook slowly for about 5 mins. or until leaves are tender & wilted.
c. 3 Tb flour
Sprinkle in flour and stir over moderate heat for 3 mins.
d. 5-1/2 cups boiling white stock (or canned chicken broth)
Off heat, beat in boiling stock. Simmer 5 mins., then pur?e through a food blender. Return to saucepan. If not served immediately, set aside uncovered. Reheat to simmer before proceeding.
e. 2 egg yolks
1/2 cup whipping cream
1-2 Tb softened butter
Blend yolks and cream in mixing bowl. Beat a cupful hot soup into them by driblets. Gradually beat the rest of soup in thin stream.
Return soup to saucepan and stir over moderate heat for 1-2 mins. to poach yolks, but do not bring soup to simmer. Off heat, stir in enrichment butter a Tb at a time.
f. watercress leaves dropped for 1/2 min. in boiling water, refreshed in cold water, drained
Pour soup into tureen or individual bowls and decorate with watercress leaves.
If you want to serve soup cold, omit final butter enrichment and chill. If you want to use sorrel or spinach, follow the same steps, but cut the leaves into thin slices (chiffonade) and do not pur?e the soup.