Gather all your ingredients and equipment to keep things organized and efficient.
Heat a tablespoon of oil in the large pot over medium heat until it shimmers and begins to smell fragrant.
Add sliced onions to the pot and cook, stirring occasionally, until they turn translucent and start to soften, about 5 minutes. The aroma will be sweet and savory as they release their aroma.
Stir in the diced carrots and celery, cooking for another 5 minutes until they begin to soften and release their color, filling the kitchen with a fresh veggie scent.
Push the vegetables to the side of the pot and place the chicken breasts in the cleared space.
Pour in the broth until the chicken is fully submerged, then bring the mixture to a gentle simmer over medium heat.
Let it simmer gently for about 20 minutes, until the chicken is cooked through and tender, and the broth is fragrant.
Remove the chicken breasts from the pot and place them on a cutting board. Shred the meat into bite-sized pieces with two forks, then return it to the soup.
Add freshly grated lemon zest and squeeze in the lemon juice, stirring well to brighten the flavors and infuse the broth with a lively tang.
Stir in chopped parsley and thyme, then season with salt and pepper to taste, adjusting until the flavors balance perfectly.
Let the soup rest off the heat for a few minutes to allow the flavors to meld and the broth to develop a clear, aromatic profile.
Serve the soup hot, garnished with extra herbs if desired, and enjoy the comforting, bright flavors with crusty bread or noodles.
