Slice the rolls in half lengthwise and spread a thin layer of mustard on both cut sides.
On the bottom half of each roll, layer 2 slices of Swiss cheese, followed by the roasted pork, ham, pickle slices, and top with the remaining 2 slices of cheese.
Place the top halves of the rolls on the sandwiches and spread the outside of each roll with softened butter.
Heat a large skillet or griddle over medium heat. Place the sandwiches in the skillet and use a heavy pot or pan to press down firmly on top.
Cook for 4-5 minutes, pressing occasionally, until the bottom is golden brown and crispy.
Carefully flip the sandwiches, press again with the heavy pot, and cook for another 4-5 minutes until both sides are golden and the cheese is completely melted.
Remove from heat, slice each sandwich diagonally in half, and serve hot. These are best enjoyed immediately while the cheese is still gooey!