To make the pudding base: Using a rolling pin, crush the biscuits in a resealable plastic bag or clean dish towel.
Divide the biscuit crumbs among 4 to 6 pudding glasses--something similar to martini glasses usually works well, or else ramekins.
For the filling: Heat the milk in a saucepan, along with the cardamom, cinnamon and vanilla bean, until just starting to boil. Remove from the heat.
In a heatproof bowl, beat the eggs well, then add the sugar, corn flour, sifted flour and salt. Mix well until combined and smooth.
Remove the cinnamon stick, cardamom and vanilla bean from the milk and slowly add the milk to the egg mixture, whisking as you do. Return everything to the saucepan; cook over low heat, stirring, until the mixture reaches a thick custard-like consistency. This takes just a couple of minutes, so keep an eye on it; you don't want it to burn.
Remove from the heat and pour into the glasses/ramekins. Leave to set at room temperature, or in the fridge if you need to speed things up.
Sprinkle with cinnamon and a light dusting of nutmeg. Refrigerate until ready to serve.