Add oil to a large pot with high sides. Add the onions, carrots, and celery, and cook over medium-low heat for 5–6 minutes, stirring often.
Stir in the tomato paste, spices, and garlic, and cook until fragrant. Add more oil if needed.
Add the chicken breasts, barley, and chicken stock. Bring to a boil, then cover and cook for 45 minutes. Check the chicken around the 25-minute mark and once it’s fully cooked, remove it and shred or dice it. Add it back to the pot about 5 minutes before the cooking time is up.
Add the frozen peas and cook for 1-2 minutes. Season the soup generously with salt and pepper and throw in some fresh parsley and parmesan cheese, if desired and enjoy!