Begin by boiling a pot of salted water and cooking the egg noodles according to package instructions. Drain and set aside.
In a large skillet, heat olive oil over medium-high heat. Add beef strips and cook until browned, about 5 minutes. Remove beef from skillet and set aside.
In the same skillet, add diced onions and garlic. Cook until onions are translucent, about 3 minutes.
Add sliced mushrooms to the skillet and cook for an additional 3 minutes.
Stir in beef broth, Dijon mustard, and Worcestershire sauce. Bring to a simmer and let cook for 5 minutes.
Add in the cooked beef strips and let simmer for another 5 minutes.
Remove from heat and stir in sour cream. Season with salt and pepper, to taste.
Serve the beef stroganoff over a bed of egg noodles and garnish with chopped parsley, if desired.