The old one I have used for years are called party rolls - a little different
It starts with a tray of those little family style finger rolls. You just dump them out connected then cut in half and put the bottom back in the pan. Brush/drizzle half of the butter mixture which consists of melted butter, mustard, dried onion flakes, and poppy seed (off the top of my head). Top with thinly sliced (I prefer it shaved into pieces) ham then swiss cheese. Place the top on the rolls. Pour remaining butter mixture over the top. Now here is the great part - you can freeze or refrigerate them at this point. I recommend at least the day before to allow the butter mixture to really soak in and flavor it all the way through. Then you bake covered for a while then uncovered. If you do it just right you will get the rolls a little crispy on the outsides! Slice the rolls along the lines (which actually this is easier done while cold before baking) and serve.