In a large saucepan, combine the brown rice, milk, sugar, and salt. Stir to mix.

Place the saucepan over medium heat and bring the mixture to a gentle boil, stirring occasionally to prevent sticking.

Once boiling, reduce the heat to low and simmer uncovered for about 50-60 minutes, or until the rice is tender and the mixture has thickened to a pudding consistency. Stir the mixture frequently to ensure even cooking and to prevent the rice from sticking to the bottom of the pan.

Remove the saucepan from the heat and stir in the vanilla extract and ground cinnamon.

If using raisins, add them to the pudding and stir to distribute evenly.

Allow the pudding to cool slightly before serving warm, or chill in the refrigerator to serve cold. The pudding will thicken as it cools.