Preheat & prep: Preheat oven to 350°F (175°C). Grease a 9×13-inch baking dish.
Slice rolls: Using a sharp bread knife, slice the slider rolls horizontally into tops and bottoms, keeping them in one sheet. Place bottoms in the dish.
Layer fillings: Evenly layer ham slices over the bottom rolls. Top with cheese, tearing to fit as needed.
Make butter glaze: In a bowl, whisk melted butter with Dijon mustard, mayonnaise, Worcestershire sauce, garlic powder, onion powder, salt, and pepper.
Glaze & assemble: Brush a generous layer of glaze over the cheese and exposed roll edges. Place roll tops back on. Brush the tops with remaining glaze.
Bake covered: Cover dish with foil and bake 10–12 minutes, until cheese is melted.
Crisp tops: Remove foil and bake 3–5 more minutes, until tops are golden brown.
Garnish & serve: Sprinkle with parsley or chives, slice apart, and serve warm.