Valentine's Beef Stroganoff- Ideals Magazine

I like vintage Ideal magazines. I love the pictures in them and really hate to tear them up so I can get a good scan. However it is just about impossible to get a quality scan from the book so I will have to make a decision.
This recipe happened to be in the same issue as a suggestion for a Valentine's dinner. I have never seen a recipe for stroganoff made like this before. You could start making the sauce while the steak is broiling and the whole dish would be finished very quickly.

Beef Stroganoff

1 pound flank steak
1 cup beef broth
1 cup chopped onion
1 pound fresh mushrooms, cleaned and sliced
1/4 cup cold water
1 tablespoons flour
1 tablespoons cornstarch
1/4 cup low-fat plain yogurt, at room temperature
1/2 teaspoon paprika
3/4 teaspoon salt
1/4 teaspoon garlic powder
12 teaspoon prepared mustard
Hot cooked noodles, optional
Preheat broiler. Broil steak 6 inches from heat until rare, about 5 minutes on each side. Cut diagonally into thin 2-inch strips' set aside. In a large frying pan bring broth to a boil. Add onion and mushrooms. Simmer, covered about 5 minutes until vegetables are tender remove vegetables with a slotted spoon; set aside. Simmer broth until reduced to 1/2 cup; remove from heat. Combine water, flour, and cornstarch mix well. Stir into broth with wire whisk. Cook and stir over low heat until thickened, about 2 minutes. Remove form heat. Combine yogurt, paprika, salt, garlic powder, and mustard to thickened broth, stirring until smooth. Mix in reserved beef, onions and mushrooms. Warm over over low heat., stirring constantly, until heated thoroughly, about 5 minutes. Serve over noodles if desired.