Preheat: Heat the oven to 350°F (175°C). Grease a 9x13-inch baking dish or line it with parchment paper.
Slice the rolls: Keeping the rolls connected, cut the whole slab in half sideways so you have one big top and one big bottom. Place the bottom half in the baking dish.
Layer: Add half the cheese, then the ham, then the rest of the cheese. Set the top half of the rolls back on.
Make the sauce: Melt the butter in a small saucepan over medium heat. Add the garlic and cook for about 1 minute, until it smells good. Stir in the honey, Dijon mustard, Worcestershire sauce, salt, pepper, and poppy seeds. Take it off the heat and stir in the parsley, if using.
Add the sauce: Pour or brush the sauce evenly over the tops of the rolls, letting it soak into all the little cracks.
Bake: Cover with foil and bake for 20 minutes. Remove the foil and bake 5 to 8 more minutes, until the tops are golden and the cheese is melted.
Rest and serve: Let the sliders rest for about 5 minutes so the cheese can set, then slice and serve warm.