This traditional recipe for russian beef stroganoff or govjadina po strogonovski or bef stroganov needs little time cooking because it's made with beef tenderloin, also known as filet mignon. While it is fully accepted that this dish is always made with thin slices of tender beef, like tenderloin or top loin, and onions, there is debate as to whether mushrooms are traditional. American versions always include them. In the states and russian-american restaurants, beef stroganoff is typically served with egg noodles or rice pilaf, but crispy pan-fried potatoes are the traditional russian way to serve stroganoff. What is unchanged, whether american or russian, is the sour-cream sauce accompanying the beef.