01 - Preheat the oven to 350°F. Grease a 9x13-inch baking dish thoroughly with butter.
02 - Spread the bread cubes evenly across the prepared dish. Distribute raisins uniformly over the bread layer.
03 - In a large mixing bowl, whisk together eggs, milk, cream, sugar, vanilla extract, cinnamon, nutmeg, and salt until completely smooth and well combined.
04 - Pour the custard mixture evenly over the bread and raisins. Press down gently to ensure all bread pieces are submerged. Allow to rest for 10 minutes so the bread fully absorbs the liquid.
05 - Bake for 40-45 minutes until the custard is completely set and the top achieves a deep golden brown color.
06 - Remove from oven and let cool slightly. Serve warm, optionally dusted with powdered sugar or drizzled with vanilla sauce.