In a large bowl, whisk together eggs, milk, half and half, sugar, vanilla, cinnamon and pinch of salt. Pour over bread cubes. Press bread cubes into the baking dish to make sure they absorb custard. Cover baking dish tightly with plastic wrap and refrigerate overnight.
Spray a 13x9 baking dish with non-stick cooking spray or butter liberally. Add bread cubes to baking dish and distribute evenly.