Sauté the onion, carrots, and celery in the soup pot until they begin to soften, then add the garlic and cook briefly until fragrant.

Pour in the chicken broth and add the boneless chicken. Bring the soup to a gentle simmer and cook until the chicken is fully cooked and tender.

Transfer the chicken to a plate, shred it once cool enough to handle, and return the meat to the pot. Cook the egg noodles separately or add them to the broth, depending on whether you plan to serve the soup immediately.

Season with salt and black pepper, then finish with fresh parsley. Taste before serving and add a little fresh lemon juice if desired for a brighter finish.