12 thin slices deli ham (about 12 ounces total), divided
Direction
Preheat the oven to 375°F.
Melt butter in the microwave or on the stove over medium heat. Add 1 tablespoon Dijon mustard, Worcestershire sauce, onion powder, and kosher salt, and whisk to combine.
Remove the slab of rolls from the package without separating rolls. Cut the slab of rolls in half horizontally. Spread the remaining Dijon mustard on each half.
Place bottom half in a 9- x 13-inch baking dish. Top with 6 slices of the Swiss cheese, overlapping slices as needed to completely cover bread. Top with 12 thin slices of ham. Layer the remaining 6 slices of Swiss cheese over the ham. Place the top half of the rolls over the cheese.
Brush the butter mixture on the top of the rolls. Cover the baking dish tightly with aluminum foil.
Bake until the sandwich is heated through and the cheese is melted, about 15 minutes. Uncover and bake until the rolls are lightly browned, 5 minutes. Transfer the slab to a cutting board and cut into individual sliders before serving.