Add the milk, sugar and rice to a medium pot, stir.

Bring to a boil on medium high heat, make sure to stir often so it doesn't stick to the bottom.

As soon as it starts to boil turn down the heat to medium low and stir. Make sure to continue stirring so it doesn't stick to the bottom.

As it thickens you'll need to turn the heat down slightly again as it will start to vigorously boil the thicker it gets. Once it starts thickening you will have to stir constantly until it reaches desired thickness to prevent it from sticking to the bottom. This takes about 15-20 minutes.

Remove from the heat once thickened and stir in the butter.

Serve in bowls and top with cinnamon sugar if you want. (To make the cinnamon sugar, mix the ingredients together and store it in a mason jar or in an air tight container)