Heat the milk in a saucepan with the vanilla pod and remove it from the heat as soon as it starts simmering.
In another saucepan whisk the eggs with the sugar and the corn starch: do it carefully to avoid any lumps. Pour slowly the hot milk in a thin stream over the eggs, stirring constantly with a whisk to prevent scrambled eggs!
Bring the saucepan back on a low flame and stir constantly with a whisk until it starts to thicken, you will need about 5 minutes. Remove the custard from the heat and divide it into two bowl. Combine the chopped dark chocolate in one bowl and whisk to melt it, until perfectly combined.
Pour half a cup of Alchermes in a bowl and add half a cup of water. Use this to soak briefly the savoiardi.
Now make the zuppa inglese in a bowl or into individual cups, by making layers of custard, savoiardi soaked in alchermes, chocolate custard and savoiardi again, until you end up with custard.
Sprinkle the surface with cocoa powder or chopped darl chocolate and let it sit in the fridge for a few hours. Take it off ten minutes before eating and enjoy with a spoon wrapped in a blanket on your couch.