Heat a skillet over medium heat. Spread butter on 1 side of all 8 slices of bread. Spread Dijon mustard on the opposite side of 4 slices of bread. Top the mustard coated bread slices with a folded slice of Emmentaler. Top cheese with slices of pickle and set tops in place with the buttered side facing up. Place the sandwiches in hot skillet and cook 3 to 4 minutes on each side, toasting and crisping the bread. Cut the sandwiches corner to corner and serve.