Preheat your oven to 350°F (175°C).
Slice the slider rolls in half horizontally without separating them.
In a bowl, mix melted butter, Dijon mustard, and poppy seeds.
Brush the bottom half of the rolls with half of the butter mixture.
Layer the sliced ham evenly over the bottom half.
Place Swiss cheese slices on top of the ham.
Brush the remaining butter mixture over the cheese.
Cover with the top half of the rolls.
Wrap the sliders in aluminum foil and place in the oven.
Bake for 15 minutes, then remove the foil and bake for an additional 10 minutes until golden brown.