2 lbs. beef tenderloin
2 tsp grated onion
1 lb. mushrooms
6 tbsp flour
1 1/2 c beef broth
1 tsp prepared mustard
1/2 c sour cream
salt and pepper to taste
1 tsp grated onion

Remove all fat and skin from meat. Cut in 1/2 x 2 inch strips. Sprinkle lightly with salt and pepper, let stand at room temperature for about 1 hour. Sauté 2 tsp onion and mushrooms in 3 Tbsp butter until slightly browned. Sprinkle with flour and mix thoroughly. Add beef broth, mustard and sour cream; stir to blend. Bring to boil. Season sauce to taste with salt and pepper, simmer 10 minutes. Melt 3 Tbsp butter in skillet; quickly brown meat strips along with 1 tsp grated onion. Add meat to sauce. Cover, keep hot for 20 minutes to blend flavors. Do not boil or simmer. When ready to serve, heat quickly over direct heat. Serve over rice or noodles.