Preheat oven to 400F
Prep the rolls by removing them from the tray and slicing them in half. Do not separate the individual rolls. Put the bottom back in the tray. Cover until later.
Grate the Swiss cheese
Prep the ham by putting it into the food processor to shred it. Remove to a bowl.
Put the onion the food processor and finely chop. Add the butter, mustard, Worcestershire, S&P, cayenne, and the poppy seeds; whir until it is a spreadable consistency.
Leaving the bottom in the tray, spread the top and the bottom of the rolls with the mixture. Add a layer of ham and a layer of cheese. Put the top on. Dab a little butter here and there on top. Cover the entire tray with foil and wrap tightly. Bake until toasty and cheese melts… about 20 minutes.
Slice in-between the rolls with a serrated knife and serve warm.