Preparation

• Arrange a rack in the middle of the oven and heat the oven to 350°F.
• Place 4 tablespoons unsalted butter in a small, microwave-safe bowl and microwave until melted, 20 to 30 seconds. Add 1 tablespoon Dijon mustard, 1 teaspoon Worcestershire sauce, ½ teaspoon onion powder, and ¼ teaspoon kosher salt, and whisk to combine.
• Cut 1 package Hawaiian sweet dinner rolls in half horizontally with a serrated knife, without separating the rolls. Place the bottom half in a baking dish.
• Arrange 6 slices of Swiss cheese on the rolls, overlapping as needed, then add 12 slices of ham, followed by the remaining 6 slices of Swiss cheese. Place the top half of the rolls over the cheese.
• Brush the butter mixture onto the top of the rolls, then sprinkle with 1 teaspoon poppy seeds. Cover the baking dish tightly with aluminum foil.
• Bake until heated through and cheese melts, about 20 minutes. Uncover and bake until lightly browned, 7 to 8 minutes. Cut into individual sliders before serving.