Bring to a steady simmer for 5 to 6 minutes, stirring as often as you can to give you a smooth creamy porridge – if you like your porridge runnier, simply add more water or nut milk until you’ve got the consistency you like. Remove the cardamom pods and cinnamon stick and discard. Ladle into deep plates and pour over some nut milk. Slice the banana and add it to the bowl, sprinkle the nuts and drizzle the maple syrup over and serve.