In a medium saucepan cook carrots in water for 15 to 20 minutes or until very tender. Drain in a colander. Transfer carrots to a blender container or food processor bowl. Cover and blend or process until carrots are smooth.

Transfer carrots to a large mixing bowl. Stir in chicken broth,white pepper, and ground ginger. Cover and chill for 2 to 24 hours.

Before serving, stir in sour cream. Top each serving with celery leaves, if desired.