Heat butter in a large pot or Dutch oven over medium-high heat.
Add beef and cook until browned. Drain excess grease if needed.
Stir in onion and mushrooms; cook 4–5 minutes until softened.
Add garlic and cook for 30 seconds until fragrant.
Stir in Worcestershire sauce, paprika, salt, and pepper.
Pour in beef broth and bring to a gentle boil.
Add egg noodles and stir well.
Reduce heat to medium-low, cover, and simmer for 10–12 minutes, stirring occasionally.
In a small bowl, whisk sour cream with flour or cornstarch until smooth.
Stir mixture into the pot and cook 2–3 minutes until creamy and thickened.
Add Parmesan cheese if using.
Garnish with fresh parsley and serve warm.