01 - Preheat 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 without separating individual rolls. Place the bottom half on a baking sheet or work surface.
03 - Arrange cheddar and mozzarella cheese slices evenly across the bottom half of the rolls, then place the top half back on.
04 - Combine softened butter with garlic powder and parsley in a small bowl. Evenly spread the mixture over the tops of the rolls.
05 - For oven method: Bake uncovered for 12–15 minutes until cheese is melted and tops are golden brown. For skillet method: Cut into individual rolls and grill each side for 2–3 minutes until golden and cheese is melted.
06 - Remove from heat, allow to cool slightly, then separate into individual rolls and serve warm.