In a large mixing bowl, whisk together the eggs, milk, vanilla extract, cinnamon, and sugar until well combined.
Preheat a large skillet or griddle over medium heat and add a tablespoon of butter, allowing it to melt and coat the surface.
Dip each slice of Hawaiian roll into the egg mixture, ensuring both sides are well coated but not overly soaked.
Place the coated rolls onto the skillet or griddle and cook for about 2-3 minutes on each side, or until golden brown and cooked through.
Remove from the skillet and keep warm while you cook the remaining slices.
Serve warm with maple syrup drizzled on top and a dusting of powdered sugar, if desired.