Melt butter over medium heat in a large soup pot. Cook onion, carrots, and celery for 8 to 10 minutes, stirring.
Add garlic, thyme, and pepper. Cook for 30 seconds.
Stir in flour and cook for 1 minute.
Gradually stir in broth until smooth. Add bay leaf and salt.
Bring to a gentle simmer, reduce heat, and cook for 5 to 7 minutes, until carrots are almost tender.
Add noodles and simmer for approximately 7 to 9 minutes, following package timing and checking early.
Reduce heat to low. Add cooked chicken and cream, then heat for approximately 3 to 5 minutes, or until the soup and chicken reach 165°F, or 74°C.
Remove bay leaf, add parsley, adjust seasoning, and serve promptly.