01 - Preheat oven to 350°F. Grease a 9x13-inch baking dish with butter or nonstick spray.
02 - Open refrigerated cinnamon roll cans. Cut each roll into quarters and distribute evenly in the prepared dish.
03 - In a mixing bowl, whisk together eggs, whole milk, heavy cream, vanilla extract, ground cinnamon, and granulated sugar until fully combined.
04 - Pour custard mixture over cinnamon roll pieces. Press gently to ensure all pieces absorb the liquid.
05 - Drizzle melted unsalted butter over the casserole and sprinkle with chopped nuts if desired.
06 - Bake uncovered for 35 to 40 minutes until golden brown and the center is set. If top browns too quickly, cover loosely with foil for the final 10 minutes.
07 - Remove casserole from oven and let rest for 10 minutes. Warm the icing packets in the microwave for 10 seconds, then drizzle evenly on top before serving.