Preheat your oven to 350°F (175°C). Grease a 9x13 inch baking dish with non-stick spray or butter.
Cut the bread into thick slices and arrange them in the greased baking dish, overlapping the slices as needed.
In a mixing bowl, whisk together the eggs, whole milk, heavy cream, granulated sugar, vanilla extract, ground cinnamon, and salt until well combined.
Pour the custard mixture evenly over the arranged bread slices, ensuring all pieces are soaked. Use a spatula to gently press down on the bread if needed.
Drizzle the melted butter over the top of the dish.
Cover the baking dish with aluminum foil and let it sit at room temperature for about 15 minutes, allowing the bread to absorb the custard.
Bake the French toast in the preheated oven for 25 minutes covered with foil, then remove the foil and bake for an additional 10-15 minutes, or until the top is golden brown and the custard is set.
Allow the dish to cool for a few minutes before serving. Dust with powdered sugar if desired, and serve with maple syrup on the side.