Heat the large soup pot over medium heat and add the olive oil, letting it shimmer and warm up.
Dice the chicken breasts into small, even pieces and season lightly with salt and pepper.
Add the chicken to the hot oil and brown for about 5 minutes, stirring occasionally until golden and cooked through.
Stir in the diced onion and minced garlic, cooking until fragrant and onions are translucent, about 3 minutes.
Pour in the chicken broth, bringing the mixture to a gentle simmer. Skim off any foam that rises to keep the broth clear.
Once simmering, add the shredded cooked chicken back into the pot along with the lemon zest, stirring to combine.
Squeeze the juice of the lemon into the soup, then simmer for another 10 minutes to let the flavors meld and the soup brighten.
Taste the broth and adjust seasoning with salt and pepper as needed, ensuring the lemon flavor is fresh and vibrant.
Once ready, ladle the hot soup into bowls, making sure each serving has tender chicken and a bright, citrusy broth.
Finish each bowl with an extra squeeze of lemon if desired, and serve immediately while steaming and flavorful.
