Mix together the milk and cream. Break open the cardamoms, extract the brown-black seeds within and grind to a fine dust. Warm the milk, cream and cardamom till almost boiling, then remove from the heat. Set the oven at 160C/gas mark 3.
Beat together the eggs and sugar till you have a thick cream, then pour on the warm milk and cream mixture and stir well. Add a few drops of vanilla extract. Butter the bread.
To prepare the apples, cut them into segments (removing the core but leaving on the peel). In a shallow pan, melt the butter, then add the apples in a single layer, letting them darken to a pale golden brown.
Turn them and cook the other side, then, when they are fully soft, sprinkle the sugar over them. Let the sugar melt and caramelise, then remove from the heat.
In a deep dish, layer the buttered bread and apples, then pour over the cardamom-scented custard. Bake for 1 hour till lightly firm but still wobbly.