6 cups day-old bread, cut into 1-inch cubes (see Chef’s Notes for best types)
2 cups whole milk (or half-and-half for extra richness)
4 large eggs
¾ cup granulated sugar
2 tablespoons unsalted butter, melted (plus more for greasing)
1 tablespoon pure vanilla extract
1 teaspoon ground cinnamon
½ teaspoon ground nutmeg
¼ teaspoon salt
½ cup raisins (optional, can be substituted with other dried fruit)
For the Vanilla Sauce (The Crown Jewel):
½ cup (1 stick) unsalted butter
1 cup heavy cream
½ cup granulated sugar
½ cup packed light brown sugar
2 teaspoons pure vanilla extract
Pinch of salt