Melt butter is small saucepan. Add next three ingredients and whisk together. Set aside.
Separate rolls into twelve pieces. An easy to do this is to cut through horizontally with a serrated knife and then cut each roll separately.
Place the bottoms in a 9x11 baking dish.
Divide the ham evenly between each roll trying to keep the ham on top of the roll. This will make it easier to pull apart the sandwiches after their heated.
Cover the top of the ham with Swiss cheese slices. No need to worry about centering the cheese. It will melt and won't interfere with pulling apart the sandwiches.
Replace the tops. Peak under the cheese to identify the mound of ham and place the top in the center of each mound.
Brush the tops of the rolls with the butter mixture. Use every last drop of it.
Sprinkle with sesame seeds. As much or as little as you like.
Cover loosely with plastic wrap and place in refrigerator for at least 4 hours up to 24 hours.
When ready to bake, remove plastic wrap. Place in a 350 degree preheated oven for 20 minutes or until cheese melts.
If sandwiches aren't going to be served immediately, separate them while the cheese is still warm.