Start by dicing the chicken breasts into bite-sized pieces.
Heat a large heavy-bottomed pot over medium heat, then add a splash of oil.
Add the diced chicken to the pot and sauté until lightly golden, about 4-5 minutes, stirring occasionally.
While the chicken cooks, zest one lemon using a microplane, then set aside.
Once the chicken is browned, add the minced garlic and cook until fragrant, about 30 seconds, until you smell the aromatic aroma of garlic.
Pour in the chicken broth, then bring the mixture to a gentle simmer.
Add the dried thyme and season with salt and pepper to taste.
Let the soup simmer uncovered for about 15 minutes, until the chicken is cooked through and the broth has a gentle, bubbling simmer.
Remove the cooked chicken from the soup and shred it into bite-sized pieces.
Return the shredded chicken to the pot, then squeeze in the juice of one lemon, stirring well.
Add the lemon zest to the soup, then simmer for another 5 minutes to meld the flavors.
Taste the soup and adjust seasonings with additional lemon juice, salt, or pepper as needed.
Garnish with chopped fresh parsley before serving, and enjoy the bright, comforting flavors of this lemon chicken soup.