01 - Preheat oven to 350°F. Generously grease a 9x13-inch baking dish to prevent sticking.
02 - Open packages and set aside icing. With a sharp knife, cut each cinnamon roll into four pieces. Distribute evenly in the greased baking dish.
03 - In a large mixing bowl, thoroughly whisk eggs, whole milk, heavy cream, granulated sugar, vanilla extract, ground cinnamon, and salt until smooth.
04 - Pour the egg mixture evenly over the cinnamon roll pieces, ensuring all pieces are soaked. Gently press rolls down with a spatula for full absorption.
05 - In a small bowl, combine melted unsalted butter, packed brown sugar, and ground cinnamon. Drizzle mixture evenly over the assembled casserole.
06 - Transfer to your oven and bake for 35 to 40 minutes until golden brown on top and the center is set. Avoid overbaking to maintain a tender texture.
07 - Allow the baked casserole to cool for 10 minutes. Warm reserved icing in the microwave for 10 to 15 seconds, then drizzle generously over the surface.
08 - Cut into portions and serve warm for best flavor and texture.