In a 4 qt pan over medium high heat add butter and olive oil, when butter is melted and bubbly add onions, celery, carrots and mushrooms. Cook stirring occasionally for 3-5 minutes then add salt, pepper, garlic, thyme and tomato paste. Continue to cook 3 more minutes then add broth, water and barley. Bring to a boil, cover and simmer 30-40 minutes. Add in chicken and simmer another 15 minutes. Taste and season with more salt and pepper if desired.