For the meringues, place the egg whites into a large, clean bowl and whisk until stiff peaks form when the whisk is removed. Gradually whisk in the sugar, a little at a time, until the mixture is glossy.
Fill a deep frying pan with boiling water. Carefully drop spoonfuls of the meringue mixture onto the surface of the water and leave for 1-2 minutes. Remove from the water with a slotted spoon and set aside.
For the custard, place the milk, cream, vanilla pod and cardamom into a saucepan and heat until almost boiling, then remove from the heat.
In a separate bowl, whisk the egg yolks and sugar together until thickened slightly, then add the warm milk mixture to the egg mixture, stirring continuously.
Pour the mixture back into the pan and cook over a low heat, stirring continuously, until the custard coats the back of a spoon. Strain the custard through a sieve into a clean bowl, discarding the vanilla and cardamom pods.
To serve, pour the custard into a serving bowl and top with the poached meringues.