1-First, heat a large pan over medium-high heat and add the oil. Sear the beef strips in batches for about 1 minute per side until they’re browned but still tender; set them aside to keep warm. This step helps lock in the flavors of the beef stroganoff.

2-Next, add the butter, onion, and mushrooms to the pan. Sauté them for 6-8 minutes until the liquid evaporates and they turn soft and browned. Then, stir in the garlic and cook for another minute until it’s fragrant.

3-Add the flour and cook for 1 minute while stirring constantly. Pour in the beef broth and heavy whipping cream, scraping up any bits from the pan, and let it simmer for 1-2 minutes until the sauce thickens slightly.

4-Finishing Touches: Temper the sour cream with a bit of the sauce before adding it back in, along with the Worcestershire sauce, Dijon mustard, salt, and black pepper. Return the beef to the pan, heat everything through, and simmer until the sauce is creamy. Serve it hot, garnished with green onion or parsley, and optionally over egg noodles.