Spread mustard generously on both cut sides of each roll.
Layer the bottom half of each roll with Swiss cheese, roasted pork, ham, pickles, and another slice of Swiss cheese. Place the top half of the roll on each sandwich.
Spread softened butter on the outside of each sandwich, coating both the top and bottom.
Heat a large skillet or panini press over medium heat and add olive oil. Place sandwiches in the pan and press down firmly with a heavy skillet or spatula.
Cook for 4-5 minutes per side, pressing occasionally, until the bread is golden brown and crispy and the cheese is completely melted. Slice diagonally and serve hot.