Prep the Ingredients: Start by dicing the onion, slicing the carrots and celery, and mincing the garlic. Zest and juice the lemon.
Combine in the Slow Cooker: In your slow cooker, add the chicken breasts, minute rice, chicken broth, diced onion, sliced carrots, sliced celery, minced garlic, lemon juice, lemon zest, and dried thyme.
Add the Butter: Place the chunks of salted butter on top of the mixture in the slow cooker.
Cook: Cover the slow cooker and cook on low for 6-8 hours, or until the chicken is cooked through and the rice is tender.
Shred the Chicken: Once cooked, shred the chicken using two forks and stir everything together well.
Garnish and Serve: Ladle the soup into bowls and garnish with freshly chopped parsley. Enjoy your comforting bowl of soup!