1. Cook the egg noodles according to package directions. Drain and set aside.

2. In a large skillet over medium-high heat, brown the ground beef. Drain excess grease.

3. Add diced onion to the skillet and cook for about 5 minutes, until softened.

4. Stir in the mushrooms and smoked turkey. Cook for another 5 minutes, until the mushrooms are tender.

5. Melt the butter in the skillet. Sprinkle in the flour and whisk constantly for 1 minute to form a roux.

6. Slowly pour in the beef broth, whisking to remove any lumps. Bring to a simmer and cook until slightly thickened, about 5 minutes.

7. Reduce the heat to low. Stir in sour cream, Dijon mustard, salt, pepper, and cayenne pepper if using. Do not let the mixture boil.

8. Serve hot over cooked egg noodles. Garnish with chopped fresh parsley if desired.