In a bowl, toss the beef strips with flour, salt, and pepper.
Heat olive oil in a large skillet over medium-high heat. Add the beef in batches and brown on all sides. Remove beef from skillet and set aside.
Add the chopped onion to the skillet and cook until softened, about 5 minutes. Add the sliced mushrooms and minced garlic and cook for another 5 minutes until mushrooms are browned and tender.
Pour in the beef broth and Worcestershire sauce. Bring to a simmer, scraping up any browned bits from the bottom of the skillet.
Return the browned beef to the skillet. Reduce heat to low, cover, and simmer for 15-20 minutes, or until the beef is tender.
Remove the skillet from the heat. Stir in the sour cream until well combined and the sauce is creamy. Do not boil after adding sour cream.
Serve the Beef Stroganoff over cooked egg noodles. Garnish with fresh chopped parsley.
Notes
For an extra rich flavor, you can add a splash of heavy cream along with the sour cream.