1. Cook pasta according to package directions, omitting salt and fat. Drain and rinse under cold water; drain.
2. Heat oil in a large nonstick skillet over medium-high heat. Add beef to pan; cook 4 minutes or until browned, stirring to crumble. Add onion, garlic, and mushrooms to pan; cook 4 minutes or until most of liquid evaporates, stirring frequently. Sprinkle with flour; cook 1 minute, stirring constantly. Stir in broth; bring to a boil. Reduce heat, and simmer 1 minute or until slightly thick. Stir in salt and pepper.
3. Remove from heat. Stir in sour cream and sherry. Serve over pasta. Sprinkle with parsley.