5 large eggs plus 2 yolks (or 6 whole eggs)
2 ¼ cups whole milk
½ cup heavy cream (or use more milk)
3 tablespoons dark rum or orange juice
2 teaspoons vanilla extract
¾ teaspoon grated nutmeg
¼ teaspoon kosher salt
1 loaf challah bread, sliced 1 inch thick, preferably stale (about 1 pound)
1 cup packed light brown sugar
8 tablespoons unsalted butter, melted
In a bowl, whisk together eggs, milk, cream, rum, vanilla, nutmeg and salt. Spread bread out in 1 layer on a large rimmed baking sheet (about 11 by 17 inches). Pour custard over bread, cover with plastic wrap, and let soak in the refrigerator for at least 4 hours or preferably overnight. Flip bread slices over once while they soak. This can be halfway through the soaking, or about an hour before baking, whichever is more convenient.
Heat oven to 375 degrees. In a medium bowl, whisk together brown sugar and butter. Pour mixture onto another large rimmed baking sheet, using a spatula if necessary to spread into an even layer.
Transfer soaked bread to sugared baking sheet, placing slices on top of the brown sugar mixture. Bake for about 25 minutes, or until tops are golden brown and sugar is bubbling.
Serve immediately while still hot, with the crunchy brown sugar side up, spooning more of pan syrup over the top.
Serve with your favorite holiday morning beverage.