Heat skillet over medium heat.
Spread 1/2 tablespoon of butter on one side of a slice of rye bread. Place butter-side down in skillet.
Spread 1 tablespoon Russian dressing on slice of rye bread in skillet. Top with corned beef, sauerkraut, and Swiss cheese.
Spread remaining Russian dressing on top of Swiss cheese.
Spread remaining butter on slice of rye bread, and place on top of Reuben, butter-side up.
Cook Reuben 5 minutes over medium heat, or until underside is golden brown. Flip Reuben, and cook additional 5 minutes, or until other side is golden brown.
Serve immediately. Yield: One Ultimate Reuben