Onion soup mix adds American ingenuity to this Russian classic.
Brown beef strips in butter. Remove from skillet. Drain mushrooms, reserving liquid, and saute in drippings in skillet. Remove from skillet. Into drippings stir a tablespoon flour and soup mix. Gradually add water and mushroom liquid, blending well and stirring until thickened. Return meat and mushrooms to skillet, cover, and simmer stirring from time to time, for about 20 minutes, or until meat is tender. Blend in sour cream and serve over hot egg noodles or boiled potatoes.