1. Heat the olive oil and 1 tablespoon of butter in a large deep skillet or Dutch oven over medium-high heat.

2. Add the beef and brown it for 3 to 4 minutes, stirring occasionally, then transfer it to a plate.

3. Add the remaining butter, onion, and mushrooms to the same pot and cook for 5 to 6 minutes until softened.

4. Stir in the garlic and cook for 30 seconds.

5. Sprinkle in the flour and stir well to coat the vegetables.

6. Pour in the beef broth, Worcestershire sauce, and Dijon mustard, stirring to combine and scraping up any browned bits.

7. Add the egg noodles and bring the mixture to a gentle simmer.

8. Cook for 8 to 10 minutes, stirring occasionally, until the noodles are tender.

9. Return the beef and its juices to the pot and stir well.

10. Reduce the heat to low and stir in the sour cream, salt, and black pepper until creamy and smooth.

11. Garnish with fresh parsley and serve hot.