MELT butter in 6-quart sauce pot on medium-high heat. Add oil, onion and garlic; cook and stir 5 minutes or until onion is tender. Add mushrooms and thyme; cook and stir 5 minutes or until mushrooms are tender.
STIR in broth and barley; bring to boil. Reduce heat to medium-low; simmer 45 minutes or until barley is tender. Stir in cheese.