Creating Ham and Cheese Sliders on Hawaiian Rolls is simple when you follow these steps:

1. Preheat Oven: Preheat your oven to 350°F (175°C).
2. Prepare Baking Dish: Grease a 9×13-inch baking dish or line it with parchment paper.
3. Slice Rolls: Without separating the rolls, cut them horizontally in half to create a top and bottom layer.
4. Layer Ham and Cheese: Place the bottom half of the rolls in the baking dish. Layer the ham evenly over the rolls, followed by the cheese slices.
5. Replace Top Half: Place the top half of the rolls back on top of the filling.
6. Create Butter Mixture: In a small bowl, mix melted butter, Dijon mustard, garlic powder, and poppy seeds (if using). Stir until well combined.
7. Brush Mixture: Brush the butter mixture generously over the top of the rolls, ensuring they are well-coated.
8. Season: Sprinkle with salt and pepper to taste.
9. Bake: Cover the baking dish with aluminum foil and bake for 15 minutes. Remove the foil and bake for an additional 10 minutes, until the cheese is melted and the tops are golden brown.
10. Serve Warm: Once ready, remove from the oven and let it cool for a few minutes before slicing into individual sliders.

With these steps, your Ham and Cheese Sliders on Hawaiian Rolls will be hot, cheesy, and incredibly delicious!