Great for a cold day.
Cut chicken into bite-sized pieces. In a large Dutch oven heat oil over medium-high heat. Add carrots, celery, mushrooms and onion. Cook until just tender, about 8 minutes. Add chicken, season with salt and pepper and cook about 2-3 minutes. Add stock and thyme and bring to a boil. Cover, reduce heat, add barley and simmer 10 to 12 minutes. Add spinach and cook until wilted, 1 minute. Season to taste with salt and pepper.