Heat a griddle pan over medium heat. Spread one side of each piece of bread with the softened butter, then flip them over so they are buttered side down. To 2 of the pieces of bread, spread the Dijon evenly over the surface. Divide the sliced onion evenly between 2 pieces of bread. Divide the cheese between the 2 pieces of bread, then cover the surface with spicy pickles. Top each sandwich with the remaining pieces of bread, buttered side out.
Using a serrated knife, cut the crusts off both sandwiches.
Add the sandwiches to the griddle pan and cook until golden brown and crisp, 2 to 3 minutes. Flip and continue to cook on the other side until the cheese has melted completely and the sandwiches are golden brown and crisp, 2 to 3 minutes.
Remove the sandwiches to a cutting board, slice into bars and serve.
Carissa’s Salty Soured Pickled Rye is available for mail order. You can also use a nice rye bread or Pullman loaf.