Season the beef strips with salt and pepper. Dredge the beef in the flour, shaking off any excess.

Heat 2 tablespoons of butter in a large skillet over medium-high heat. Add the beef strips and cook until browned on both sides, about 5-7 minutes. Remove the beef from the skillet and set it aside on a plate.

In the same skillet, add the remaining 2 tablespoons of butter. Add the onions and mushrooms and sauté until softened and the mushrooms have released their juices, about 5-7 minutes. Add the garlic and sauté for an additional minute.

Add the beef broth and Worcestershire sauce to the skillet, stirring to combine. Bring the mixture to a simmer and let it cook for 5-7 minutes, or until the liquid has reduced by half.

Reduce the heat to low and stir in the sour cream. Add the beef back to the skillet and let it simmer for an additional 5-10 minutes, or until the sauce has thickened and the beef is cooked through.

Serve the beef stroganoff over rice or even cooked egg noodles, garnished with additional sour cream and chopped parsley, if desired.