Preheat your oven to 350°F (175°C).

In a small bowl, mix together the melted butter, Dijon mustard, Worcestershire sauce, garlic powder, onion powder, and a pinch of salt and pepper.

Slice the slider rolls in half horizontally and place the bottom halves in a greased baking dish.

Layer the ham slices evenly over the bottom halves of the rolls.

Top the ham with Swiss cheese slices.

Place the top halves of the rolls on the cheese.

Brush the butter mixture generously over the tops of the rolls.

Sprinkle poppy seeds evenly on top.

Cover the dish with aluminum 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.

Remove from the oven, let cool slightly, then slice and serve warm.