In a mixing bowl, whisk together eggs, milk, vanilla extract, and cinnamon.
Slice Hawaiian rolls in half horizontally.
Dip each piece of roll into the egg mixture, ensuring it's well coated.
Heat a skillet or griddle over medium heat and add butter.
Cook each piece until golden brown on both sides, about 2–3 minutes per side.
Serve warm with maple syrup or a dusting of powdered sugar.