Butter 1 side of each bread slice, then put 4 slices, buttered side down, on a work surface. Top the bread slices with the smoked ham, then the teleme cheese, distributing it evenly. Top each with a second slice of bread, buttered side up.
Heat a panini pan/sandwich griller until hot. Heat the sandwich in the griller, with a weight on top to keep as flat as possible. Cook until nicely browned, 2 to 3 minutes,
Transfer the sandwiches to a work surface and remove the top slice of bread from each sandwich. Spread the underside of those slices with mustard, and add roasted peppers, if desired.
Replace the top slice of bread, cut the sandwiches in half, and serve immediately.