Steps

1. Preheat a sandwich press on a medium setting.  Alternately, heat two large, heavy skillets of the same size over medium heat.  Preheat the oven to 300°F and set a rack on a baking sheet.
2. Spread mustard on the top and bottom halves of the bread. Portion the cheese evenly over all the bread halves, followed by a layer of pickles and then a layer of roast pork. Season with salt and pepper. Finally place a layer of sliced ham on the four bottom halves of bread.
3. Gently but firmly press on all the bread halves to help the toppings adhere.  Close the sandwiches by placing the tops onto the bottoms.  Press on the sandwiches to flatten them out somewhat.
4. Brush the top and bottom crusts of the sandwiches with the melted butter and, working in batches, place them into the sandwich press.
5. If you are using skillets, place two sandwiches in one of the skillets and set the other skillet on top.  Turn the heat to low.  Use an oven mitt or potholder to press down on the top skillet for a few seconds.  Cook the sandwiches for about three minutes, and then remove the top skillet and check to see that the bottoms are golden brown.  If not, replace the top skillet and continue cooking.  When the bottoms of the sandwiches are browned, turn them over and replace the top skillet.  Raise the heat to moderate and cook about a minute more until the new bottoms are golden brown.
6. Transfer the sandwiches to a cutting board and cut each one in half on the diagonal. Serve immediately or keep warm on the rack in the oven while you prepare the remaining sandwiches.

Notes

No one is exactly sure when the Cuban sandwich was invented or who is responsible for creating it. Most food historians believe that these tasty hot sandwiches first became popular in Ybor City, a neighborhood of Tampa, Florida, around 1900. At that time a large influx of Cubans migrated to the area to work in cigar factories. Tampa had also attracted a significant number of Italian immigrants, many of whom opened sandwich shops catering to the factory workers. Some of these Italian entrepreneurs adapted the newly-invented Italian panini press to the Cuban workers’ favorite bread and sandwich fillings—and the Cuban Sandwich, or Cubano as it became known, was born. Before long, sandwich shops in Miami, in the Florida Keys, and even in Cuba were making these special sandwiches, each with its own local variations.

This version of the Cuban sandwich is Miami style, the kind preferred by purists. A Tampa Cubano includes Genoa salami. To make a Key West Cuban, spread the bread with mayonnaise as well as mustard, and add lettuce and tomato after the sandwich is heated.