Prep the pan: Grease a 9x13-inch baking dish with butter. This helps the edges crisp and prevents sticking.
Cut the rolls: Open the cinnamon roll cans and set aside the icing packets.
Cut each unbaked roll into 4–6 pieces. Scatter the pieces evenly in the baking dish.
Make the custard: In a large bowl, whisk together eggs, milk, cream, vanilla, cinnamon, nutmeg, brown sugar, melted butter, and a pinch of salt until smooth.
Combine: Pour the custard evenly over the cinnamon roll pieces. Gently press down so every piece soaks a bit.
Rest time: Let it sit for 15–20 minutes at room temperature to absorb.
For best flavor and texture, cover and refrigerate overnight.
Preheat: When ready to bake, preheat the oven to 350°F (175°C). If chilled, let the dish sit on the counter while the oven preheats.
Bake: Bake uncovered for 35–45 minutes, until the center is set and the top is golden. If the top browns too quickly, tent with foil for the last 10 minutes.
Finish with icing: Warm the icing packets in a bowl of hot water for 2–3 minutes.
Drizzle over the hot bake. For a thicker glaze, beat the icing with 2 oz softened cream cheese before drizzling.
Serve: Let it rest for 5–10 minutes. Serve warm with maple syrup, an extra sprinkle of cinnamon, or a dusting of powdered sugar.