Gather all your ingredients and prep your vegetables by dicing carrots, celery, and onion. Shred the cooked chicken and have fresh herbs, lemon, and seasonings ready.
Heat olive oil in a large heavy-bottomed pot over medium heat. Add diced onions, carrots, and celery. Sauté gently, stirring occasionally, until the vegetables are tender and fragrant, about 8 minutes. You should hear a gentle sizzle and see the vegetables soften and become slightly translucent.
Pour in the chicken broth and bring the mixture to a gentle simmer. Use a ladle to skim off any foam or excess fat that rises to the surface. Let it simmer uncovered for about 10 minutes, allowing the flavors to meld and vegetables to soften further.
Add the shredded cooked chicken and dried thyme to the simmering broth. Stir well and cook for another 5 minutes until the chicken is heated through. The soup should be bubbling gently, with the flavors blending nicely.
Remove the pot from heat. Stir in the lemon zest, lemon juice, and chopped parsley. Season with salt and pepper to taste. The lemon and herbs will brighten the broth and give it a lively aroma.
Ladle the bright, clear soup into bowls. Garnish with additional parsley if desired. Serve hot, with a slice of crusty bread if you like, and enjoy the comforting, zesty flavors.
