Sirloin Stroganoff

Cut off the fat from the steak. Cut the beef into thin slices diagonally across the fibers. Set aside.Preheat a large nonstick skillet coated with cooking spray over medium-high heat. Add the onion; simmer for 6 minutes. Add the mushrooms; simmer for 4 minutes or until tender.Combine the flour and the following 3 ingredients in a bowl. Add the beef, stirring until it is coated. Heat the oil in a large skillet over high heat. Add beef; simmer 6 minutes or until beef is tender. Add the remaining onion mixture and stock. Bring to a boil, reduce the heat, and simmer for 2 minutes or until the sauce thickens. Remove from heat; add sour cream. Sprinkle with parsley. Serve with noodles.