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 in half horizontally while keeping them connected. Place the bottom half on a baking sheet or cutting board.
03 - Distribute cheddar and mozzarella 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 softened butter with garlic powder and chopped parsley. Mix until well blended.
05 - Spread the garlic-parsley butter mixture evenly over the top of the rolls, ensuring full coverage for a golden crust.
06 - 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 cheese.
07 - Remove from heat and let rest for 2 minutes. Separate into individual mini sandwiches and serve warm.