Heat olive oil in a large pot over medium-high heat.
Add the diced beef and season with salt and pepper. Brown the beef on all sides, about 5-7 minutes.
Remove the beef and set aside. In the same pot, add the onions and sauté until translucent, about 3-4 minutes.
Add the garlic and mushrooms, cooking until the mushrooms are tender, about 5 minutes.
Pour in the beef broth, Worcestershire sauce, and Dijon mustard. Stir to combine all the ingredients.
Return the beef to the pot, cover, and let it simmer for 15 minutes.
Stir in the sour cream until fully incorporated and let it heat through for 2-3 minutes.
Meanwhile, cook the egg noodles in a separate pot according to package instructions.
Drain the noodles and serve them topped with the beef stroganoff. Garnish with fresh parsley if desired.