Preheat oven to 350 degrees. Slice 9 Hawaiian rolls in half, so there is a top and bottom sheet of rolls. Place bottom half sheet of rolls in 8x8 baking dish.
Spread ¼ c mayonnaise on bottom ½ of rolls. Place 4-6 thick slices of ham and 4 slices of swiss cheese between top and bottom of the rolls.
Mix together butter mixture. Add 1 T butter, 1 T dijon mustard, ¼ tsp garlic salt, ¼ tsp Worcestershire sauce, and 1 tsp poppy seeds to a microwave safe bowl. Microwave until butter is mostly melted, about 15 seconds.
Pour butter mixture over rolls, spread evenly with the back of a spoon or pastry brush. Cover with oven safe silicon lid or tin foil. Bake for 12 minutes, then uncover and bake for 3 more, or until crispy and browned.
Remove from oven when browned, and transfer to a cutting board with a spatula or just flip the sliders over onto the cutting board. Slice into 9 sliders with a serrated knife, serve immediately or refrigerate for leftovers.