Pat the chicken thighs dry with paper towels and season generously with salt & pepper.

Heat the oil in a dutch oven over medium-high heat.

Brown the chicken thighs in the hot oil on each side, about 5 minutes per side (you may need to do this in batches). Transfer browned chicken to a plate and set aside.

Discard all but 1 tsp oil from the pot and keep over medium-high heat. Add the onion, carrot, celery, and bell pepper. Cook until vegetables begin to soften, about 3 minutes.

Add the garlic and cook until fragrant, about 10 seconds. Add the chicken stock, oregano, parsley, basil, rosemary, red pepper flakes, bay leaf, and ½ tsp salt. Using a wooden spoon scrape the bottom of the pot to release any stuck on bits. Bring to a boil.

Return the chicken and any remaining juices to the pot and reduce heat to medium-low. Cover and simmer for 30 minutes or until chicken is cooked through.

Transfer the chicken thighs to a plate, shred the chicken using two forks and discard the skin and bones. Return the shredded chicken back into the pot. Place a lid back on the pot and reduce heat to low.

Add water to a separate pot and cook the campanelle according to package directions then drain and add to the soup along with the spinach. Cook for 2 more minutes to heat through.

Season soup with salt & pepper to taste. Ladle soup into bowls and top with shaved Parmesan.