Heat olive oil in a Dutch oven or large pot over medium-high heat. Add the onions and garlic and sauté one minute.
Add the carrots and celery, along with the thyme, salt and pepper. Sauté together for about 2 minutes, to soften the veggies.
Pour in the chicken stock, lemon juice, add the chicken and rice and bring to a boil. Then lower to medium-low heat, cover, and simmer for about 20-30 minutes, stirring the soup every 10 minutes or so. Cook just until the rice and chicken are both cooked (see Notes).
Serve garnished with chopped fresh parsley.
Notes
Makes approximately 6 servings.How to tell when chicken is done: Chicken is cooked when a thermometer inserted into the thickest part of the meat has an internal temperature of 165°F. Storage: allow the soup to cool, then store in an airtight container in the refrigerator for up to 4-5 days. You can also store in freezer bags or an airtight freezer-safe container for up to two months.