Place chopped carrots, celery, and onion in the bottom of the slow cooker.
Add the chicken pieces on top of the vegetables.
Pour in chicken broth until ingredients are mostly covered. Add seasonings.
Cover and cook on LOW for 6–8 hours or HIGH for 3–4 hours until chicken is cooked through and vegetables are tender.
About 30 minutes before serving, stir in heavy cream or cream of chicken soup. Adjust seasoning and serve warm.
Notes
For extra flavor, sauté onions and garlic before adding. Add noodles or rice in the last hour for a heartier soup. Leftovers taste even better the next day.