Preheat your oven to 350°F (175°C). Grease a casserole dish with butter or non-stick cooking spray.
2. In a large bowl, combine the milk, eggs, sugar, vanilla extract, cinnamon, nutmeg, and salt. Whisk until well blended.
3. Add the bread cubes to the mixture and gently stir until they are all coated. Let the mixture sit for 10 minutes, allowing the bread to soak up the custard.
4. If using raisins, fold them into the bread mixture.
5. Pour the melted butter evenly over the mixture and gently toss to distribute it.
6. Transfer the bread pudding mixture to the greased casserole dish, spreading it out evenly.
7. Bake in the preheated oven for 45-55 minutes or until the top is golden brown, and the center is set. You can test for doneness by inserting a toothpick into the center; it should come out clean.
8. While the bread pudding is baking, prepare the vanilla sauce. In a small saucepan, combine the heavy cream, sugar, butter, and brown sugar. Heat over medium heat, stirring constantly, until the sauce thickens and coats the back of a spoon. Do not let it boil. Remove from heat and stir in the vanilla extract.
9. Once the bread pudding is done, remove it from the oven and allow it to cool slightly. Serve warm, drizzled with the vanilla sauce.

Each mouthful of this bread pudding in casserole with vanilla sauce will transport you to a place of pure bliss. The combination of soft, custardy bread, warm spices, and the heavenly touch of the vanilla sauce is a symphony for your taste buds. Save this recipe, not just for its incredible taste, but also for the memories it will create—moments shared with loved ones, tales told, and hearts warmed. Indulge in this delightful treat, and let the flavors dance on your palate, bringing comfort and joy to your soul.