Add honey, nutmeg, cardamom, cinnamon stick and coconut milk. Turn up heat to medium and stir until well combined and mixture just comes to a boil. Turn down heat to low, cover and let simmer for 20-30 minutes, stirring occasionally. Add a bit more milk if it's looking dry.
Before serving, remove cinnamon stick and stir to combine. Garnish with toasted pistachios for a bit of crunch and a sprinkle of ground cinnamon. We like ours with a bit of half and half or coconut milk on top too.