Cook Tortellini noodles, drain, and keep warm.

Meanwhile, cook beef, mushrooms, onion, and garlic in skillet over med/high heat until beef is browned. Drain and return to skillet.

Add flour, stirring constantly for 2 minutes. Gradually add beef broth and cook until thickened.

Stir in sour cream and Tortellini, top with cheese, cover, and cook until cheese is melted.