1. Preheat oven to 350°F. Slice rolls horizontally, all the way through. Keeping them together as a unit. Spread mustard on one side.
2. Fold a piece of ham on each roll, repeat until all ham is used.
3. In a medium-size bowl, whisk together eggs and milk. Scramble eggs and pour over ham. Sprinkle with cheese. Bake for 15 minutes, or until cheese is melted and sandwiches are heated through.
TIP: To get a head start you can slice the rolls and spread the mustard and add the ham. Wrap well in saran wrap and refrigerate for up to 2 days.