Preheat your oven to 350°F (175°C).
Slice the slider buns in half horizontally.
Place the bottom halves in a greased baking dish.
Layer half of the ham slices on the buns.
Add a layer of cheese on top of the ham.
Top with the remaining ham slices.
Add the top halves of the buns.
In a bowl, mix melted butter, Dijon mustard, poppy seeds, salt, and pepper.
Brush the butter mixture generously over the top of the buns.
Bake in the preheated oven for 20 minutes or until golden brown and the cheese is melted.