Preheat your oven to 350°F (175°C) and grease a 9x13-inch baking dish.
Place the cubed Hawaiian rolls in the prepared baking dish. If using, sprinkle the chopped pecans evenly over the rolls.
In a large mixing bowl, whisk together the eggs, milk, heavy cream, granulated sugar, vanilla extract, ground cinnamon, and salt until well combined.
Pour the egg mixture evenly over the cubed rolls, ensuring all pieces are soaked. Gently press down on the rolls to help them absorb the liquid.
Cover the baking dish with aluminum foil and let it sit for about 15 minutes to allow the rolls to soak up the mixture.
Bake in the preheated oven for 25 minutes covered, then remove the foil and bake for an additional 15-20 minutes, or until the top is golden brown and the center is set.
Remove from the oven and let it cool for a few minutes before serving. Dust with powdered sugar and serve with maple syrup if desired.