Celery leaves (optional)
1/2 tsp. black pepper
1/2 tsp. kosher salt
6 oz. uncooked medium egg noodles
1 cup chopped onion
2 cups diagonally sliced celery
2 cups diagonally sliced carrot
12 oz. skinless, bone-in chicken breast half
2 skinless, bone-in chicken thighs
8 cups Chicken Stock or fat-free, lower-sodium chicken broth