Preheat your oven to 350°F (175°C).
Slice the slider buns in half horizontally.
Place the bottom halves of the buns in a greased baking dish.
Layer half of the ham over the buns.
Add a layer of Swiss cheese over the ham.
Place the remaining ham on top of the cheese.
Add another layer of Swiss cheese over the second ham layer.
Replace the top halves of the buns.
In a bowl, mix melted butter, Dijon mustard, poppy seeds, garlic powder, salt, and pepper.
Brush the mixture generously over the top of the sliders.
Cover the dish with foil and bake for 15 minutes.
Remove the foil and bake for an additional 10 minutes until golden brown.