Preheat oven to 180C
Brush a round or rectangle baking dish with melted butter
In a bowl, whisk together milk, eggs, vanilla extract, sugar, salt, cinnamon powder, nutmeg powder and the remaining butter till properly combined
Lightly soak each slice of bread for about 5 seconds in this mixture, turning it to soak both ways and arrange on the baking dish like shown in the video. Pour any extra egg mixture all over the bread. Let this soak for 20 minutes
When ready to bake, sprinkle with chopped nuts and some more sugar
Bake in a preheated oven at 180C for 35-40 mins. Once baked, remove from oven, and let the pudding cool. Once cool, cover with aluminium foil and and refrigerate for at least an hour or two. Serve cold with some rum custard sauce.
For Rum Custard Sauce
In a pan, slowly bring the milk to a simmer. Turn off the heat.
In a large bowl, whisk together egg, sugar, vanilla and salt till light and fluffy.
Add hot milk in a slow stream to the egg mixture while whisking vigorously so that the egg doesn't scramble. This method is called tempering, and ensures that the egg is cooked without scrambling. It's important to add milk slowly so that the egg doesn't cook too quickly.
Strain the mixture into another pan if required. Now put this pan on a slow flame and keep stirring till the mixture starts to thicken up. As soon as the mixture starts coating the back of a spoon, take it off heat and transfer to another bowl. Again it's important to warm up the egg mixture slowly and keep stirring so that it doesn't curdle. Stir in the rum at this point.
Let the custard cool down to room temperature, after which it can be refrigerated in an airtight container for up to 3 days. Serve with cold cinnamon bread pudding.