Preheat oven to 375 degrees.
Spray a 9x13 baking dish with non-stick cooking spray. Set aside.
Open the cinnamon rolls and separate the rolls. Set the icing aside.
Cut each cinnamon roll into 4 equal pieces. Place the cinnamon roll pieces into a large mixing bowl. Pour melted butter on top of cinnamon roll pieces, and stir to coat the rolls.
Pour the coated cinnamon roll pieces into the baking dish.
In a medium bowl whisk together the eggs, milk, cinnamon and vanilla. Pour over the cinnamon rolls.
Drizzle with maple syrup on the top of the cinnamon rolls.
Bake for 25-30 minutes or until cooked through.
While the cinnamon roll casserole is baking, make the frosting. Whisk together powdered sugar and milk until it reaches a frosting consistency. Add in the icing from the cinnamon roll tubes. Mix to combine. Set in refrigerator while you wait for the casserole to finish baking.
Remove from oven and let cool.
Frost the cooled cinnamon roll casserole with the icing. You can also chose to separate the frosting in half and put half on while the casserole is warm so the frosting drips into the warm dish. Then, wait until it's cooled, and frost with the remaining frosting.