Preheat a large griddle or skillet over medium heat. 

Spread dressing evenly over one side of all the bread slices. 

On half of the bread slices, layer on top of the dressing one slice of cheese, two slices of corned beef, 1/4 c. of sauerkraut, and top with a second slice of cheese. Place a second slice of bread dressing side down on top of the cheese. 

Butter the top of each sandwich.

Place sandwiches on the griddle butter side down. While grilling, butter the side of the sandwich now showing in the griddle. 

Grill for 5 minutes and flip, grilling the second side for about 5 minutes or until both sides are golden brown. 

Serve hot.