Heat a heavy-bottomed pot over medium heat, then add olive oil and sauté diced onions, carrots, and celery until fragrant and slightly translucent, about 5 minutes. The vegetables should smell sweet and start to soften.
Add the bone-in chicken thighs to the pot, searing them until golden brown on both sides, about 7 minutes. Use tongs to flip the chicken carefully, and listen for a gentle sizzle.
Pour in the chicken stock, ensuring it covers all ingredients. Bring the mixture to a gentle simmer, then reduce the heat to low and skim off any foam that rises to the surface with a ladle. Add thyme and bay leaves.
Cover the pot partially and let it simmer quietly for about 1 hour, stirring occasionally. The chicken should become tender and start to fall apart, and the broth will develop a rich, savory aroma.
Remove the chicken thighs from the pot and place them on a cutting board. Shred the meat with forks, discarding the bones, and return the shredded chicken to the broth.
Taste the broth and season with salt and pepper as needed. Squeeze in fresh lemon juice to add brightness and balance the flavors.
Ladle the hot soup into bowls, garnish with chopped parsley, and serve immediately with crusty bread for a complete, warming meal.
Enjoy the comforting warmth of this hearty chicken soup, with tender shredded meat and a bright, flavorful broth.
