1/4 cup reduced fat or regular Thousand Island dressing
Lightly spread butter on one side of each bread slice.
Heat large nonstick skillet over medium heat until hot. Place 2 bread slices, butter side down, in skillet. Top each bread slice with 2 slices cheese, 1 tablespoon dressing, 3 ounces corned beef and 1/4 of the sauerkraut.
Top with 2 bread slices butter side up.
Cook sandwiches 4 to 6 minutes or until bread is golden brown and cheese is melted, turning once. Repeat with remaining sandwiches. Serve with additional Thousand Island dressing, if desired.