Preheat your oven to 350°F (175°C). Grease a 2-quart baking dish.
In a large bowl, combine milk, melted butter, sugar, beaten eggs, vanilla extract, cinnamon, and salt.
Add the bread cubes and raisins (if using), and stir gently to coat.
Pour the mixture into the prepared baking dish and bake for 40–45 minutes, or until a knife inserted in the center comes out clean.
Serve warm with vanilla sauce.