Preheat the oven to 350°F (175°C) and prepare a 9x13-inch baking dish by greasing it lightly.
In a spacious mixing bowl, combine the eggs, milk, both sugars, vanilla, cinnamon, and nutmeg. Whisk thoroughly until the mixture is uniform.
Fold the bread cubes into the custard base, stirring gently to ensure even coating. Set the mixture aside for 15 to 20 minutes to allow the bread to soak fully.
Transfer the soaked bread mixture into the prepared baking pan. Pour the melted butter over the top evenly. Sprinkle with your choice of optional ingredients such as nuts, dried fruit, or chocolate.
Place the dish in the oven and bake for 45 to 50 minutes, uncovered, until the top is golden brown and the custard has set in the center.
Allow the pudding to cool briefly before serving. Present warm with vanilla cream, whipped topping, or a scoop of ice cream if desired.