Prepare the baking dish: Generously butter a 9×13-inch baking dish. Arrange the French bread slices in a single layer, slightly overlapping if necessary.
Make the custard: In a large mixing bowl, whisk together the eggs, half-and-half, milk, vanilla extract, sugar, cinnamon, and nutmeg until smooth and well-combined.
Soak the bread: Pour the custard mixture evenly over the bread slices, ensuring every slice is thoroughly coated. Use a spatula or your hands to gently press the bread into the custard.
Refrigerate overnight: Cover the dish tightly with plastic wrap and refrigerate overnight to allow the bread to absorb the custard.
Bake the French toast: Preheat your oven to 350°F (175°C). Remove the baking dish from the refrigerator and discard the plastic wrap. Dot the bread with small pieces of butter and sprinkle a light layer of sugar over the top. Bake for 35-40 minutes, or until the French toast is puffed and golden.
Caramelize the sugar topping: Remove the dish from the oven and let it cool slightly. Sprinkle an even layer of granulated sugar on top of the bread. Use a kitchen torch or the broiler setting on your oven to caramelize the sugar until it is golden and crisp.
Serve: Allow the French toast to cool for a few minutes before serving. Drizzle with maple syrup and enjoy!
