Heat the olive oil in a large skillet over medium-high heat. Add the beef strips and cook until browned. Remove the beef from the skillet and set aside.
In the same skillet, add the diced onion and cook until softened, about 3-4 minutes. Add the minced garlic and sliced mushrooms, and cook until the mushrooms are tender.
Sprinkle the flour over the vegetables and stir to combine. Gradually add the beef broth, stirring constantly, until the mixture starts to thicken.
Stir in the Worcestershire sauce and return the beef to the skillet. Reduce the heat to low and simmer for about 10 minutes.
Remove the skillet from heat and stir in the sour cream. Season with salt and pepper to taste.
Serve the beef stroganoff over cooked egg noodles, garnished with chopped parsley.