For the bread pudding, preheat the oven to 350°F, with a rack in the middle. Lightly butter an 8-by-11-inch baking pan or a 10-inch cast-iron skillet.
In a large bowl, whisk together the milk, sugar, and eggs until smooth. Slowly whisk in the butter, vanilla, cinnamon, and nutmeg. If you like the flavor of nutmeg, you can add a few more shakes.
Tear a bun into approximately 1-inch pieces and add to the wet mixture. Repeat, using half of the buns.
Mash the buns with a spoon into the wet mixture until moistened. Tear the remaining buns and add to the mixture. Mash until combined, but don’t mash them so much that the mixture turns to mush. The bread should be completely moistened with some bun pieces still retaining most of their shape. Add more cinnamon or nutmeg, if desired. Scrape the mixture into the baking pan.
Bake for about 45 minutes, or until the pudding is sponge-like and springs back when touched in the middle. Feel free to make a judgment call on the baking time. You don’t want it to bake completely through like a cake; remember it’s bread pudding. You can err on the side of not cooking the pudding quite as long, because it will set up a little more after it cools.
While the bread pudding is cooking, make the whiskey cream sauce. Whisk together the melted butter and sugar in a medium saucepan on low heat. Whisk in the cream and then add the whiskey and bring to boil. Reduce to a simmer to cook off the alcohol, but be careful not to scorch the cream.
Drizzle or drench the bread pudding with whiskey cream sauce. Serve warm or at room temperature.