2 lbs. boneless round or chuck, or flank steak, cut into strips
1/2 lb. mushrooms, sliced
2 tbsp. butter
1 env. Lipton onion or beefy onion soup mix
2 1/4 c. water
3 tbsp. all-purpose flour
1/2 c. sour cream

Melt butter and brown beef with mushrooms. Add soup mix blended with 1 3/4 cups water. Simmer covered, stirring occasionally, about 40 minutes or until beef is tender. Stir in flour blended with sour cream and remaining water. Bring to boiling point, then simmer, stirring occasionally, until sauce is thickened. Serve over cooked noodles.