Rinse rice and pour warm water on top.
Add cinnamon stick and cardamom pods. Cover and let the rice soak overnight or for at least 10 hours.
Puree the soaked rice in a blender along with cinnamon stick and cardamom pods.
Strain pureed rice and water through muslin cloth, squeezing it firmly to extract as much flavor as possible.
Blend the powdered sugar and coconut milk with the rice extract.
Serve chilled in a tall glass with ice. Sprinkle flaked almonds on top for texture.