Prepare the Sliders. Preheat your oven to 350°F. Slice the Hawaiian rolls in half horizontally, keeping them connected. Place the bottom half of the rolls in a baking dish.
Layer the Filling. Layer the thinly sliced ham evenly over the rolls. Add a layer of Swiss cheese over the ham.
Assemble the Top Layer. Place the top half of the rolls over the cheese, resealing the connected rolls.
Prepare the Glaze. In a bowl, whisk together melted butter, Dijon mustard, Worcestershire sauce, poppy seeds, dried minced onion, salt, and pepper.
Apply the Glaze. Generously brush the glaze over the tops and sides of the sliders.
Bake to Perfection. Cover the baking dish with aluminum foil and bake in the preheated oven for 15-20 minutes or until the cheese is melted and the sliders are heated through. Uncover and bake for an additional 5 minutes or until the tops are golden brown.
Serve and Enjoy. Remove from the oven, let them cool for a few minutes, then slice along the original roll lines.