Preheat your oven to 350˚F, then pour the melted butter into a 9x13-inch baking dish and spread it evenly over the bottom.
Open the cans of cinnamon rolls and set aside the glaze.
Cut each cinnamon roll into quarters and spread the pieces evenly over the melted butter in the baking dish.
In a mixing bowl, whisk together the beaten eggs, milk, vanilla, cinnamon, and maple syrup until well combined.
Pour the mixture over the cut-up cinnamon rolls in the baking dish. Gently press down on the cinnamon rolls with a fork. Sprinkle the chopped nuts evenly over the top of the casserole.
Bake the breakfast casserole for 35 to 40 minutes or until the top is golden brown and puffy.
Remove the cinnamon roll casserole from the oven and let it cool for 5 minutes, then drizzle the glaze over the top.
Garnish with more nuts and serve warm.
Notes
Make Ahead: You can assemble the cinnamon roll casserole up to a day in advance, then cover it and place it in the fridge until you're ready to bake it.
Glaze: If your canned cinnamon rolls didn't come with icing, you can make your own. Just mix 1 tablespoon powdered sugar with 1 tablespoon milk, then stir in 3 tablespoons of softened cream cheese until smooth.
Storage: Store leftovers in an airtight container in the fridge for up to 4 days. Eat cold or reheat in the microwave in 20-second increments until warm throughout.
Cinnamon Rolls: This casserole is made with a total of 16 cinnamon rolls. I used Pillsbury Cinnamon Rolls, but you can use any brand you like or make your own using my recipe for from-scratch cinnamon rolls.