• 1 loaf challah bread, sliced 1 in. thick, preferably stale (about 1 lb.)
• 1 c. packed light brown sugar
• 8 tbsp. 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.