Spread desired amount of dressing on each slice of rye bread. Arrange corned beef, sauerkraut and cheese on two slices; top each with remaining bread slices. Spread desired amount of butter over each top slice of bread. Arrange sandwiches, buttered side down, on griddle. Grill over medium heat until bottoms are golden-brown (about 5 min.). Butter top slices of bread; flip and continue cooking until bottoms are golden-brown and cheese is melted (about 5 min.).
Variation: For a Rachel Sandwich, substitute thinly sliced turkey for the corned beef.