Heat A Skillet Over Medium Heat. Spread Butter Over One Side Of One Slice Of Bread. Place Bread Butter-Side-Down Into Skillet, And Top With Tempeh, Swiss Cheese, And Then Sauerkraut. Spread Butter On The Remaining Slice Of Bread, And Place On Top Of Sauerkraut. Cook Until Toasted On One Side, Flip, And Continue Cooking Until Cheese Melts.