Cut chicken breasts into bite size pieces and season with salt & pepper. Heat olive oil in a 2-3 qt saucepan.
Add Chicken and cook until no longer pink. Remove from pan with a slotted spoon and set aside.
Add 2 tablespoons of butter to the same pan and add the onion, carrots and celery. Cook for 5 min or until onions are translucent. Add Garlic, Thyme & Cayenne, Salt & Pepper. Cook for another 3 minutes.
Add flour to the vegetables and cook for 1 minute longer. Add the Chicken stock slowly to mixture. Cook for 20 minutes or until vegetables are tender and soup thickens.
Add the Half & Half & cook and stir until thickened. Add Chicken and Spinach, cooking for another 5-10 min. Check the seasonings and add more Salt, Pepper or Cayenne to taste.