1 lb. sirloin, cut in thin strips
5 tbsp. butter
2 tbsp. flour
2 c. beef bouillon
3 or 4 tbsp. sour cream
2 tbsp. tomato paste
3 tbsp. (or more) chopped onion
Mushrooms and sherry (optional)

Melt 2 tablespoons butter, add flour, blend. Stir in beef bouillon and cook to thicken. Boil 2 minutes. Add sour cream and tomato paste. Stir constantly until mixed thoroughly. Simmer gently. Fry beef in 3 tablespoons butter, add onion. When browned, add to sauce. Simmer at least 1 hour. Sherry and mushrooms may be added. Serve over rice.