Preheat your oven to 350°F (175°C).
Slice the slider buns in half and place the bottom halves in a baking dish.
Layer slices of ham evenly over the bun bottoms.
Add Swiss cheese slices on top of the ham.
Place the top halves of the buns over the cheese.
In a bowl, mix melted butter, Dijon mustard, and poppy seeds.
Brush the butter mixture generously over the slider tops.
Cover the dish with aluminum foil and bake for 15 minutes.
Remove the foil and bake for an additional 5 minutes until golden brown.
Remove from the oven, let cool slightly, and serve warm.