Preheat & prep the dish
Preheat your oven to 350°F (175°C). Lightly grease a 9×13-inch baking pan so the pudding doesn’t stick.

Cube the bread
Tear or slice the stale bread into roughly 1-inch pieces and spread them evenly across the prepared baking dish.

Whisk the custard
In a large mixing bowl, whisk together the eggnog, eggs, sugar, vanilla, cinnamon, nutmeg, and salt until the mixture is smooth and uniform.

Soak the bread
Pour the custard evenly over the bread cubes, pressing down gently with a spatula so the pieces absorb the liquid. Let the pan sit for about 10 minutes so the bread becomes fully saturated.

Add butter and bake
Drizzle the melted butter over the top of the soaked bread. Place the dish in the oven and bake for 45–50 minutes, until the surface is nicely golden and the center is set.

Cool & serve
Remove from the oven and let the pudding rest for about 15 minutes. Serve warm, dusted with powdered sugar, topped with a drizzle of caramel sauce, or a generous dollop of whipped cream.