Heat olive oil in a large skillet over medium-high heat. Add the sliced beef and cook until browned, about 3-4 minutes. Remove the beef from the skillet and set aside.
In the same skillet, add the chopped onion and cook until translucent, about 3 minutes. Stir in the minced garlic and sliced mushrooms, cooking until the mushrooms are tender, about 5 minutes.
Return the beef to the skillet and add the beef broth, Worcestershire sauce, and Dijon mustard. Bring to a simmer and let cook for 5 minutes.
Reduce the heat to low and stir in the sour cream until well combined. Season with salt and pepper to taste.
Meanwhile, cook the egg noodles according to package instructions. Drain and set aside.
Serve the beef stroganoff over the egg noodles and garnish with chopped parsley.