In a large bowl, combine eggs, milk, vanilla and spices. Add in croissant cubes and mix until properly coated. Cover and let soak overnight.
Heat the oven at 350 degrees. Mix croissant egg mixture before pouring into a buttered baking dish or ramekins. Set aside.
In a small saucepan, add butter and gently melt over medium heat. Remove melted butter and stir in brown sugar and syrup until well combined. Pour over croissant mixture and bake uncovered for 35 - 40 minutes or until golden brown.
Serve warm with a side of warm syrup and/or clotted cream.
Recipe by jessica burns at http://jessicaburns.com/2015/04/croissant-french-toast-bake/