1Place strips into flour seasoned w/salt, pepper and garlic powder.
In a large skillet, quickly brown them on both sides in the olive oil and butter.
Remove the steak from the pan.
Add the onion slices and mushrooms to the pan drippings.
Saute for a few minutes, until the onion is tender. Sprinkle with 1 teaspoon flour.
Put the steak back into the pan with the onion and mushrooms.
Add the mushroom soup and beef broth.
Cook over low heat for about 30 minutes, covered. Adjust seasoning to taste, adding salt and pepper, as needed.
Stir in the sour cream the last few minutes, right before you serve.
Serve over cooked noodles.