Brown ground beef in a saucepan over medium heat until no pink remains, breaking it down as it cooks.
Add onions, garlic, and mushrooms. Cook for 5-7 minutes or until onions are translucent and mushrooms are soft. Add flour, and stir until evenly coated.
Add beef broth, heavy cream, and worcestershire. Cook for an additional 5-7 minutes or until sauce has thickened. Add salt and pepper to taste.
Remove from heat. Stir in sour cream. Garnish with parsley, and serve over egg noodles, rice, or mashed potatoes.