Preheat your oven to 350°F (175°C) and lightly spray a 9×13-inch baking dish with nonstick cooking spray.

Cube the bread and place it evenly in the prepared baking dish.

In a bowl, whisk together eggs, milk, cinnamon, and vanilla until smooth.

Pour the custard mixture over the bread cubes, pressing gently to ensure all pieces are coated. Cover and refrigerate overnight.

Remove from the fridge for 30 minutes before baking. Bake for 45-50 minutes until golden brown and puffed up.

Let cool slightly before serving; dust with powdered sugar or drizzle with maple syrup.