01 - Preheat oven to 350°F. Lightly grease a 9x13-inch baking dish.
02 - Place the cubed cinnamon rolls evenly in the prepared baking dish.
03 - In a large mixing bowl, whisk together whole milk, heavy cream, eggs, granulated sugar, brown sugar, vanilla extract, cinnamon, nutmeg, and salt until smooth.
04 - Pour the custard evenly over the cinnamon roll cubes, gently pressing down to ensure all pieces soak up the liquid.
05 - Allow the mixture to sit for 10 to 15 minutes to fully absorb the custard.
06 - Bake for 35 to 40 minutes until the top is golden and custard is set but slightly wobbly in the center.
07 - While baking, whisk powdered sugar, milk, and vanilla extract in a small bowl until smooth and pourable.
08 - Remove from oven and cool for 10 minutes before drizzling with icing to serve.