Preheat the oven to 350°F (175°C)
Grease a baking dish with butter
Cut bread into cubes
Place bread cubes in a large mixing bowl
Whisk together eggs, milk, sugar, melted butter, vanilla extract, cinnamon, and salt
Pour the custard mixture over the bread cubes
Stir gently to coat all the bread
Let the mixture sit for 10 to 15 minutes
Add raisins, nuts, or chocolate chips if desired
Transfer the mixture to the prepared baking dish
Bake for 40 to 50 minutes until set and golden brown
Remove from the oven and let cool slightly
Serve warm plain or with sauce, cream, or ice cream