Preheat your oven to 325°F (165°C). Line a 9x13-inch baking dish with parchment paper or aluminum foil, leaving an overhang on the sides to use as handles for easy removal.

Keep the Hawaiian rolls connected and use a serrated knife to slice the entire block horizontally into two halves. Place the bottom half into the prepared baking dish.

Layer the sliced smoked ham, roasted turkey, and grated Gruyère cheese evenly across the bottom half of the rolls.

In a small mixing bowl, whisk together the melted butter, beaten egg, Worcestershire sauce, Dijon mustard, and mayonnaise until the sauce is smooth and well combined.

Drizzle approximately half of the prepared butter sauce over the meat and cheese layers.

Place the top half of the rolls over the filling. Brush the remaining sauce evenly over the tops of the rolls, ensuring they are well coated.

Bake uncovered for 25 to 30 minutes, or until the cheese is melted and the tops of the rolls are golden brown. If they brown too quickly, cover loosely with foil.

Allow the sliders to rest for 5 to 10 minutes. Lift them out of the pan using the parchment handles, slice into individual sandwiches, dust generously with powdered sugar, and serve with raspberry preserves for dipping.