Preheat the Oven:
Preheat your oven to 350°F (175°C).
Prepare the Rolls:
Without separating the rolls, slice them horizontally in half to create a top and bottom layer. Place the bottom layer in a greased baking dish.
Layer the Fillings:
Spread mayonnaise or mustard (if using) over the bottom layer of rolls. Layer the ham or turkey evenly, then top with cheese slices. Place the top half of the rolls back on.
Make the Glaze:
In a small bowl, combine melted butter, Worcestershire sauce, Dijon mustard, onion powder, and poppy seeds. Mix well.
Brush with Glaze:
Generously brush the glaze over the tops of the rolls, making sure they are evenly coated.
Bake:
Cover the dish with foil and bake for 15 minutes. Remove the foil and bake for an additional 5–10 minutes, or until the tops are golden brown and the cheese is melted.
Serve:
Remove from the oven, let cool for a few minutes, then slice and serve warm.