Keep the Hawaiian rolls attached to each other. Using a serrated knife, slice the entire slab of rolls in half horizontally to create one large top bun and one large bottom bun.

Mix the softened butter with garlic powder (if using). Spread the butter evenly over the cut sides of the rolls (the sides that will touch the pan).

Heat a large skillet or griddle over medium-low heat. Place the bottom slab of rolls into the pan, buttered side down.

Immediately layer the cheddar cheese and the mozzarella cheese evenly across the bread. Place the top slab of rolls over the cheese, buttered side facing up.

Cook for 3 to 4 minutes until the bottom is deeply golden brown. You can cover the pan with a lid to help the cheese melt faster.

Using a large spatula, carefully flip the entire slab of rolls over. Cook for another 3 to 4 minutes on the second side until golden brown and the cheese is fully melted.

Remove from the pan and let rest for 1 minute on a cutting board. Use a knife to slice along the seams into 12 individual mini grilled cheese sandwiches.

Garnish with fresh chopped parsley and serve immediately.