Preheat oven to 375 degrees and lightly grease a 9-inch baking dish or similar sized casserole dish.
Slice rolls crosswise so that the rolls are split in half. (Do not separate the rolls, they should all still be connected when you slice them so that the bottom halves stay connected and the top halves stay connected)
Spread mayo over the bottom halves. Top with ham slices, then swiss cheese, and then pineapple slices. Top with the top halves of the rolls
In a small bowl whisk together melted butter, dijon mustard, brown sugar, garlic powder, and poppy seeds. Brush mixture over the sandwiches.
Bake for 10-15 minutes until cheese is melty and sliders are browned on top.
Video
Notes
These can be made in advance, covered tightly and stored in the fridge up to 24 hours, and baked just before serving. If baking after chilling, add 10 minutes to baking time.