Rinse the Arborio rice under cold water until the water runs clear to remove excess starch.
In a large saucepan, combine the rinsed rice, whole milk, coconut milk, the split vanilla bean pod, and the scraped vanilla seeds.
Add sugar and salt to the mixture, stirring well to combine.
Bring the mixture to a gentle boil over medium heat, then reduce the heat to low, stirring occasionally to prevent sticking.
Simmer gently for about 30-35 minutes, or until the rice is tender and the pudding has thickened to your desired consistency. If it becomes too thick, you can add a little more milk to loosen it up.
Once the rice is cooked, remove the saucepan from the heat. Discard the vanilla bean pod and stir in the ground cinnamon (if using) and vanilla extract.
Allow the pudding to cool slightly before serving or refrigerating. It can be enjoyed warm or chilled.
Notes
Serve warm or chilled, garnished with fresh berries and toasted coconut flakes.