01 - Preheat the oven to 350°F. Line a rimmed baking sheet with parchment paper and set aside.
02 - Using a serrated bread knife, slice the entire block of Hawaiian rolls in half horizontally, keeping them connected. Do not separate into individual rolls.
03 - Place the bottom half of the rolls on the prepared baking sheet. Arrange the cheddar and mozzarella cheese slices in an even layer across the surface, covering it completely.
04 - Place the top half of the rolls back over the cheese layer, pressing down gently to create a unified sandwich slab.
05 - In a small mixing bowl, whisk together the melted butter, garlic powder, dried parsley, and sea salt until well combined.
06 - Using a pastry brush, generously coat the tops and sides of the assembled rolls with the garlic butter mixture, ensuring even coverage.
07 - Loosely tent the rolls with aluminum foil and bake for 10 minutes, allowing the cheese to begin melting.
08 - Remove the foil and continue baking for an additional 5 minutes, or until the cheese is fully melted and the tops are golden brown and slightly crisp.
09 - Remove from the oven and let rest for 2 to 3 minutes. Using a sharp knife, cut along the roll seams to separate into 12 individual mini sandwiches. Serve immediately while warm.