1. Sprinkle both sides of meat with garlic salt. Place in 3-quart (13x9) glass baking dish. Cover with plastic wrap.
2. Microwave on SIMMER for 45 minutes. Turn meat over; recover, and continue cooking on SIMMER for 40 to 45 minutes or until fork tender. Remove meat to platter; cover, and chill several hours. Dissolve onion soup mix in hot meat juices; set aside.