1. Saute the onion, celery, and carrots in butter in a saucepan. Cook until everything is tender.
2. Stir in chicken broth and simmer for 5 minutes.
3. Stir in the remaining ingredients and simmer for about 10 minutes, stirring occasionally.
This soup is super quick for a couple reasons. The chicken and rice are leftovers, already cooked, and you use canned chicken broth. Also, you are going to saute the finely chopped onion, celery, and carrots which make them soften very quickly; much more quickly than trying to cook celery and carrots in the soup itself. Good, simple soup.