Cook egg noodles according to package directions. Drain and set aside.
Brown beef in a large skillet over medium-high 5-7 minutes, breaking up with a spoon; drain excess fat if needed.
Add onion and mushrooms; cook about 5 minutes until softened. Add garlic; cook 1 minute more until fragrant.
Sprinkle flour over beef; stir to coat evenly and cook 1-2 minutes.
Slowly add broth and Worcestershire, stirring constantly; simmer 3-4 minutes until sauce thickens.
Off heat, stir in sour cream, salt, and pepper until smooth and creamy.
Serve over cooked noodles; garnish with fresh parsley if desired.