Cut steak into thin strips. In a large skillet (oven-proof, if desired), brown meat
in oil, using high heat. Add onions. Saute until tender crisp. Blend soup, sherry,
liquid from mushrooms, and garlic salt. Pour over steak. Add mushrooms. Reduce heat;
cover and simmer 1 hour or until steak is tender. (Or cover and bake at 350 degrees.)
Serve over rice.