Preheat oven to 350 degrees F
Spray a 9x13-inch baking dish with non-stick spray
In a bowl or large measuring cup, mix together butter, Dijon mustard, Worcestershire sauce and poppy seeds.
Separate the tops from bottoms of the rolls, and place the bottom pieces into the baking dish.
Layer half the ham onto the rolls. Place the Swiss cheese over the ham, and top with remaining ham slices.
Place the tops of the rolls onto the sandwiches.
Lightly brush the top and sides of the rolls with the butter mixture with a pastry brush.
Pour the remaining butter sauce into the bottom of the dish
Bake in the preheated oven until the rolls are lightly browned and the cheese has melted, for about 20 minutes.
Slice into individual rolls to serve!