Strain broth and reserve chicken. When chicken is cool enough to handle, remove skin and cut meat into bite-size pieces.
Add onions, celery, carrots, potatoes and soup base to broth and bring to a boil. Add chicken and cook until vegetables are tender. Salt and pepper to taste.
For dumplings, beat egg. Add remaining ingredients. Mix and drop by teaspoons into broth. Bring soup to a light boil. Soup must be boiling to cook dumplings properly. Cook about 15-20 minutes.