Melt butter in a large nonstick skillet over medium heat.
Add onion, garlic, and mushrooms; cook, stirring frequently, 7 minutes or until mushrooms are tender. Stir in crumbles, broth, Worcestershire sauce, and pepper; cook 2 minutes. Reduce heat to medium-low; stir in soup. Fold in sour cream, and cook until thoroughly heated (do not boil).