Preheat the oven to 350°F (175°C).
Cut the slider rolls in half horizontally and place the bottom halves in a greased baking dish.
Layer the ham evenly over the bottom halves of the rolls.
Place a slice of Swiss cheese on top of the ham for each slider.
In a bowl, combine melted butter, Dijon mustard, garlic powder, and poppy seeds.
Brush the mixture generously over the tops of the slider rolls.
Cover the baking dish with foil and bake for 15 minutes.
Remove the foil and bake for an additional 10 minutes or until golden brown.
Let the sliders cool for a few minutes before serving.