Preheat a sandwich press or grill pan over medium heat.
Slice the Cuban bread loaf in half lengthwise. Spread yellow mustard on one half and mayonnaise on the other half.
On the mustard side, layer the roast pork, ham, Swiss cheese, and pickles.
Top with the mayonnaise side of the bread.
Spread butter on the outside of the sandwich.
Place the sandwich in the preheated press or pan.
Grill for about 3-5 minutes on each side, or until the bread is crispy and the cheese is melted.
Remove from the heat and cut the sandwich into halves or quarters.
Enjoy your meal!