Combine the first seven ingredients. Brush over both sides of the steaks and onion slices. Grill over hot heat, turning once, 15-20 minutes or until steaks have reached desired doneness and onion is tender. Brush occasionally with sauce during grilling. Serve onion slices alongside each steak.
Top loin steak may be labeled as strip steak, Kansas City steak, New York strip steak, ambassador steak or boneless club steak in your region.