Combine Lipton® Recipe Secrets® Onion Mushroom Soup Mix, water and ground beef in large bowl; shape into 6 patties.
Grill or broil burgers, turning once, until done, about 10 minutes.
Evenly top with cheese and cook until cheese is melted, about 2 minutes.
Arrange burgers on bread, then top with caraway seeds and, if desired, heated sauerkraut and thousand island dressing.