Gather all your ingredients and equipment to keep the process smooth and enjoyable.
Heat the olive oil in a large heavy-bottomed pot over medium heat until it shimmers and begins to smell fragrant.
Add the diced onion, carrots, and celery to the pot. Sauté, stirring occasionally, until the vegetables are soft, translucent, and fragrant, about 8 minutes. You’ll notice the aroma intensify and the vegetables turn slightly golden.
Stir in the dried thyme and cook for another minute to release their fragrant oils.
Pour in the chicken broth and bring the mixture to a gentle simmer. Let it cook uncovered for 10 minutes, allowing the flavors to meld and the vegetables to soften further.
Add the shredded cooked chicken to the broth, stirring to combine. Continue to simmer for another 5 minutes to heat the chicken through.
Slice the lemon in half and squeeze in the juice, stirring well. This brightens the broth and adds a lively zing to each spoonful.
Taste the soup and season with salt and pepper as needed. Adjust the lemon juice for more brightness if desired.
Remove the pot from heat and let the soup rest for 2-3 minutes, allowing flavors to settle.
Ladle the bright, clear soup into bowls, garnishing each with chopped fresh parsley for a fresh, herbal finish.
Enjoy your lemon herb chicken soup hot, savoring the comforting yet lively flavors with each spoonful.