Cinnamon roll casserole tastes just like decadent cinnamon rolls, but without all the effort! This baked cinnamon roll casserole recipe is the ultimate brunch dish, made with Pillsbury refrigerated cinnamon rolls, eggs, milk, a touch of maple syrup, and a drizzle of icing over the top. It's super easy to make ahead and is perfect for the holidays, especially Christmas morning. An overnight sweet treat that will be the hit of any breakfast or brunch!