1 Can quick-frozen cream of potato soup 1 soup can milk 2 C. washed -- drained finely cut watercress Thaw soup a little by placing opened can in a pan of hot water. Pour into glass container of electric mixer or blender or food processor. Add milk and watercress. Blend until smooth. Refrigerate until well chilled. Just before serving, pour into blender again and blend a few seconds. If too thick, add a little cold milk or cream. Serve in chilled soup cups. Makes 3 or 4 servings.