Add rice, butter, water and salt in a pot and bring to a boil
Put the lid on and let it simmer for 10 min
Heat up the milk in the microwave but take it out before it starts to bubble
Add milk and cinnamon stick to the pot and stir it together
Stir while bringing it to boil, lower the temperature to the lowest and put the lid on. Keep watch so it does not boil over and let it simmer for 40 min or longer
Serve with sugar and cinnamon on top and cold milk around it