In a large skillet, heat the olive oil over medium heat. Add the chopped onion and minced garlic, sautéing until the onion is translucent, about 3-4 minutes.

Add the ground beef to the skillet, breaking it apart with a spatula. Cook until browned, about 5-7 minutes. Drain any excess fat.

Stir in the sliced mushrooms, salt, pepper, Worcestershire sauce, and Dijon mustard. Cook for another 5 minutes until the mushrooms are tender.

Sprinkle the flour over the mixture and stir well to combine. Gradually add the beef broth while stirring continuously to avoid lumps. Bring to a simmer and cook for about 5 minutes until the sauce thickens.

Reduce the heat to low and stir in the sour cream until fully incorporated. Do not boil after adding sour cream to prevent curdling.

Meanwhile, cook the egg noodles according to package instructions. Drain and set aside.

Serve the beef stroganoff over the cooked egg noodles and garnish with fresh parsley.