01 - Preheat oven to 350°F or set a large skillet or griddle over medium heat.
02 - Using a serrated knife, slice the entire connected slab of Hawaiian rolls in half horizontally without separating individual rolls. Place the bottom half on a baking sheet or flat work surface.
03 - Distribute cheddar and mozzarella cheese slices evenly across the bottom half of the rolls, covering the full surface. Place the top half of the rolls back in position.
04 - In a small bowl, combine softened butter with garlic powder and chopped parsley. Brush or spread the mixture evenly over the tops of the rolls.
05 - For oven method: bake uncovered for 12 to 15 minutes until cheese is fully melted and tops are golden brown. For skillet method: cut into individual rolls and grill each side for 2 to 3 minutes until golden with melted centers.
06 - Remove from heat and allow to rest briefly. Separate into individual mini sandwiches and serve warm.