Combine watercres, onion, celery, sugar, cornstarch and 2 cups bouillon in container of electric blender; process until smooth. Pour watercress mixture into a saucepan; add remaining bouillon and stir well. Bring to a boil. Reduce heat, and simmer 10 minutes, stirring constantly. Stir in evaporated milk, butter and salt; simmer 3 to 5 minutes, stirring occasionally. Garnish individual servings with watercress leaves, if desired. Yield: 8 to 10 servings. Mrs. R. V. Forrester, Springfield, Virginia. Recipe by: Southeren Living, April 1979 Posted to MC-Recipe Digest by Barb at PK on Apr 17, 1998