Grease a baking dish with melted butter.
In a large bowl, combine the stale bread cubes and eggnog. Let soak for 30 minutes to 1 hour.
In a separate bowl, whisk together the eggs, granulated sugar, vanilla extract, nutmeg, and cinnamon.
Pour the egg mixture over the bread and eggnog mixture. Stir gently to combine.
Pour the mixture into the prepared baking dish.
Bake at 325°F (160°C) for 60 minutes, or until a knife inserted into the center comes out with just a few moist crumbs clinging to it.
While the bread pudding is baking, prepare the rum sauce. In a saucepan, melt the butter over medium heat.
Add the brown sugar and stir until dissolved.
Stir in the heavy cream, rum, vanilla extract, and salt.
Bring to a simmer and cook for 5-7 minutes, or until the sauce has thickened slightly.
Let the bread pudding cool slightly before serving. Drizzle with warm rum sauce.
Serve and enjoy!
