In a small bowl, soak raisin in rum 30-60 minutes (or even longer if desired)
Preheat oven to 350 ℉. In a bowl, beat the eggs. Mix in milk, cream, granulated sugar, salt and nutmeg. Set aside.
Cut 6 slices of bread and butter both sides VERY generously. Set aside.
Drain raisins and reserve the rum. *Add the rum to the milk mixture. This is a better time to add the remaining rum vs. in the video, when I added the rum just before putting the pudding in the oven. This ensures the rum is evenly distributed. Either way, it tastes delicious.
In a baking dish, place a layer of bread and sprinkle with raisins. Add another layer of bread and sprinkle with raisins again.
Pour milk/egg/rum mixture all over the bread. Soak for 10 minutes.
Pour remaining butter, melted (or 3 Tbs) all over the top.
Sprinkle with dark muscovado sugar.
Bake in preheated oven for 30 minutes. Serve hot, with lots of cream poured on top and/or vanilla ice cream.