In a bowl, mix together melted butter, Dijon mustard, minced onion, poppy seeds. Set aside.
Cut the slider buns in half. Place the bottom halves in a baking dish.
Spread mayonnaise on the buns. Layer Swiss cheese, ham and Swiss cheese on top. Cover with the top halves of the buns.
Brush the glaze generously over the top of the sliders, making sure to cover them evenly.
Cover the baking dish with aluminum foil and bake for 15 minutes. Then, remove the foil and bake for an additional 5-10 minutes or until the tops are lightly browned and crispy.
Video
Notes
Nutrition information is an estimation and will vary depending on the brands used to make these rolls.