Start by gathering all your ingredients and chopping the carrots, celery, and onion into bite-sized pieces. Prepare your workspace to keep things organized.
Heat a heavy-bottomed pot over medium heat, then add a splash of olive oil. Once shimmering, add the diced onions, carrots, and celery, stirring occasionally. Cook until the vegetables soften and release a sweet aroma, about 8 minutes.
Add the minced garlic to the vegetables and cook for another minute, until it becomes fragrant and slightly golden.
Nestle the bone-in chicken thighs into the pot, turning them to brown each side for about 5 minutes until golden and slightly crisp.
Pour in the chicken broth, then sprinkle in the red pepper flakes. Bring the mixture to a gentle simmer, watching the broth bubble softly.
Reduce the heat to low, cover the pot with a lid, and let the soup simmer for about 45 minutes to an hour. During this time, the chicken will become tender and start to fall apart, enriching the broth with flavor.
Once cooked, carefully remove the chicken thighs from the pot. Use two forks or a meat shredder to pull the chicken into shredded pieces.
Return the shredded chicken to the pot, stirring to combine. Taste the broth and adjust seasoning with salt and pepper as needed.
Let the soup rest for 10 minutes, uncovered, allowing flavors to meld and the broth to thicken slightly. The vegetables should be tender, and the chicken flavorful and juicy.
Serve the soup hot, ladled into bowls. Garnish with fresh herbs or a squeeze of lemon if desired, and enjoy this comforting, rustic dish.
