Preheat your oven to 350°F (175°C).
Slice the Hawaiian rolls in half horizontally.
Place the bottom halves in a greased baking dish.
Layer the deli meat evenly on the bottom halves.
Add a slice of cheese on top of the meat for each slider.
In a bowl, mix melted butter and Dijon mustard.
Brush the butter mixture over the cheese.
Sprinkle poppy seeds on top if using.
Cover with the top halves of the rolls.
Bake for 15-20 minutes until the cheese is melted and the tops are golden.