Place the whole chicken or chicken parts in a large stockpot, then cover with cold water and bring to a gentle simmer over medium heat. As it heats, skim off any foam that rises to the surface, which helps keep the broth clear.
Add the quartered onion, whole garlic cloves, carrots, celery, and sprigs of thyme to the pot. Let everything simmer gently for about 1.5 hours, maintaining a steady, gentle bubbling—avoid a vigorous boil to keep the broth clear and flavorful.
Once the chicken is tender and falling apart, carefully remove it from the pot and set aside to cool slightly. Strain the broth through a fine-mesh strainer into a clean container, discarding the solids.
Shred the cooked chicken meat using a sharp knife or hands, removing skin and bones. Return the shredded chicken to the strained broth.
Add sliced carrots and celery back into the broth, then bring to a gentle simmer for about 15 minutes until the vegetables are tender but not mushy.
Stir in lemon zest and a splash of lemon juice to brighten the flavors, then season with salt and pepper to taste. Let the soup rest for a few minutes so the flavors meld.
Garnish with freshly chopped parsley before serving, adding a fresh, herbal note that complements the smoky broth.
Serve hot in bowls, with a side of crusty bread if desired, and enjoy the comforting aroma of this classic chicken soup.
