Preheat your oven to 350°F (175°C). Grease a 9x13-inch baking dish with cooking spray or butter.
Cut the Hawaiian rolls in half horizontally and arrange the bottom halves in the prepared baking dish.
In a large mixing bowl, whisk together the eggs, whole milk, heavy cream, granulated sugar, vanilla extract, ground cinnamon, and salt until well combined.
Pour the egg mixture evenly over the rolls in the baking dish, ensuring all pieces are soaked.
Drizzle the melted butter over the top of the casserole.
Cover the dish with aluminum foil and let it sit for about 30 minutes to allow the rolls to absorb the egg mixture.
Bake covered for 25 minutes, then remove the foil and bake for an additional 15-20 minutes, or until the top is golden brown and the center is set.
Allow to cool for a few minutes before serving. Dust with powdered sugar and serve with maple syrup.