Thaw meat in refrigerator and thinly slice while partially frozen. Heat heavy skillet over medium high heat. Add 1 tbsp. butter and quickly sauté Beef Tenderloin Tips until well browned. Remove meat and keep warm. Add remaining 2 tbsp. butter to skillet. Sauté onions until very tender, 6-7 minutes. Add mushrooms and sauté 5 minutes. Stir in flour, blending until completely mixed into butter. Stir in beef broth, wine and seasonings. Heat to simmer. Stir in browned meat. Reduce heat to low. Blend in sour cream. Stir until sauce is heated and smooth. Serve over hot noodles.