Step 1: Boil salted water in a large pot and cook the egg noodles according to the package instructions. Drain and set aside.
Step 2: In a large skillet over medium-high heat, brown the ground beef until no longer pink. Drain excess grease, leaving about 2 tablespoons in the pan.
Step 3: Add diced onions and sliced mushrooms to the skillet. Sauté for 5-7 minutes until onions are soft and mushrooms are browned. Stir in the minced garlic and cook for 30 seconds.
Step 4: Sprinkle flour over the beef and vegetable mixture, stirring continuously for 1 minute to cook the flour.
Step 5: Gradually pour in the beef broth, scraping the bottom of the pan to release browned bits. Stir in Worcestershire sauce and Dijon mustard.
Step 6: Bring the sauce to a gentle simmer, reduce heat to low, and let it thicken for 5 minutes.
Step 7: Remove the skillet from the heat entirely. Stir in the sour cream until the sauce is smooth and creamy. Season with salt and pepper to taste.
Step 8: Serve the warm beef mixture immediately over the cooked egg noodles. Garnish with chopped fresh parsley.
