1 1/2 lb. beef tenderloin
5 tbsp. butter
1 lg. onion, sliced
1/2 lb. mushrooms
1/2 c. dry wine
1 1/2 c. sour cream
2 tbsp. tomato paste

Cut beef into 1/2 inch slices. Cook strips in 3 tablespoons butter until brown. Saute onion and mushrooms in remaining butter. Return meat to pan. Add wine, stir in sour cream and tomato paste. Cook until heated through.