Beef Stroganoff - Russian Style

1 pound sirloin steak cut into thin strips 3 tablespoons flour, all-purpose divided 1/2 teaspoon salt 4 tablespoons butter or margarine 3 ounces mushrooms,[...]

2 lbs lean boneless sirloin (trimmed of fat and gristle) or 2 lbs bottom round steaks , in one piece (trimmed of fat and gristle) 2 teaspoons salt 1/2[...]