The custard needs to be cold, so we can make that first. Whisk all the ingredients together and cook till boiled. The custard won't be thick, it will be flowy. Allow to cool completely and refrigerate till serving.
For the pudding base, beat eggs for a couple of minutes till homogenous. Add the milk and sugar and whisk. Keep on low flame and cook till the mixture is slightly glossy, thick and cooked. Add the vanilla and switch off.
In a small saucepan, toss the apples, brown sugar, cinnamon and vanilla extract. Cook for around 10 minutes, just for the apples to soften slightly.
Into a deep dish pan, layer the apples. Add the chopped bread, the nuts and raisins and toss everything together.
Pour the pudding mixture all over allowing it to soak for 10 minutes. Meanwhile, preheat the oven to 180 degrees.
Bake for 20 minutes if you need a little fluid in your final pudding or for 30 minutes for a harder one.
Serve warm with the cold custard.