Bring stock to a boil over medium heat. Add onion, carrots, celery, rice and thyme, then reduce heat to low, cover and let simmer for 30 minutes.
Add chicken and cook for an additional 5 minutes.
Ladle soup into 4 bowls. If using miso, stir in 1 tablespoon into each bowl and garnish with cilantro if using. Serve with sourdough, buns or a side salad.
Notes
MODIFICATIONS:To make it vegan, replace the chicken stock and chicken with vegetable broth and 1-2 cups cooked beans. Throw in a tablespoon of nutritional yeast for some extra vitamin Bs. Add in some chopped red pepper, bok choi, green beans or a little kale. See what you have on hand, want to use up and experiment to find your favorite mix.