01 - Preheat the oven to 350°F or set a large skillet or griddle over medium heat.
02 - Using a serrated knife, slice the entire sheet of Hawaiian rolls horizontally in one piece without separating individual rolls. Place the bottom half on a baking sheet or clean work surface.
03 - Arrange cheddar and mozzarella cheese slices evenly across the bottom half of the rolls, covering the entire surface. Place the top half of the rolls back over the cheese layer.
04 - In a small bowl, combine the softened butter with garlic powder and chopped parsley. Mix thoroughly until evenly incorporated.
05 - Spread the garlic butter mixture evenly over the top of the rolls using a pastry brush or the back of a spoon, ensuring full coverage for a golden, crispy finish.
06 - For oven method: Bake uncovered for 12 to 15 minutes until the cheese is fully melted and tops are golden brown. For skillet method: Cut into individual sandwiches and grill each side for 2 to 3 minutes until golden with melted cheese centers.
07 - Remove from heat and allow to cool for 2 to 3 minutes. Separate into individual mini sandwiches and serve warm.