Bring a large pot of salted water to a boil and cook the egg noodles according to package directions until al dente. Drain and set aside.
Heat a large skillet over medium-high heat.
Add the ground beef and cook for 5–7 minutes, breaking it into crumbles, until browned and cooked through.
Drain excess grease if necessary and temporarily transfer the beef to a plate.
Reduce the heat to medium and add the butter to the skillet.
Add the mushrooms and onion and cook for approximately 5 minutes until the mushrooms are browned and the onion is tender.
Add the garlic and cook for 30 seconds.
Sprinkle the flour over the vegetables and stir continuously for 1 minute.
Slowly pour in the beef broth while stirring.
Add the Worcestershire sauce, Dijon mustard, paprika, salt, and black pepper.
Bring to a gentle simmer.
Return the browned ground beef to the skillet and simmer for 3–4 minutes until the sauce thickens.
Reduce the heat to low.
Stir in the sour cream until smooth and creamy. Do not boil.
Add the drained egg noodles and gently toss until evenly coated.
Taste and adjust the seasoning.
Garnish with fresh parsley and black pepper before serving.