Spread butter on one side of each of the 4 bread pieces. Heat a griddle pan to medium high heat. Place 4 pieces of bread on the griddle, buttered side down. On each piece, spread some shredded cheese, sauerkraut, Russian dressing, more cheese, and then another piece of bread. When the bottom bread is browned, flip the sandwich and cook until the bread is toasted and the cheese is melted.