01 - Preheat oven to 350°F. Line a baking sheet with parchment paper.
02 - Using a serrated bread knife, slice the entire block of Hawaiian rolls horizontally, creating a top and bottom slab without separating individual rolls.
03 - Place the bottom half of rolls onto the prepared baking sheet. Evenly layer sliced cheddar cheese over the rolls, then add deli ham or turkey if using.
04 - Set the top half of the rolls over the cheese and fillings to complete assembly.
05 - Combine melted butter with mustard, honey, and garlic powder if desired. Brush this mixture over the tops of the rolls using a pastry brush.
06 - Bake in the preheated oven for 10 to 15 minutes, or until the cheese is fully melted and the roll tops develop a golden crust.
07 - Cool for 2 minutes, then separate into 12 mini sandwiches. Serve warm.