Heat the milk. Cool it and chill it in the refrigerator.
Mash the bananas and whisk in the mixie till finely mashed. Mix into the cold milk.
Just before serving the shake, place 3 ice cubes in each of the tall glasses.
Whisk the fruit and milk mixture in a mixie and pour into the tall glasses. Sprinkle pinches of the cardamom-nutmeg on top of each glass and serve imediately.