01 - Preheat the oven to 325°F. Lightly grease a 2-quart baking dish with a small amount of butter.
02 - Rinse the rice under cold water until the water runs clear. Drain thoroughly.
03 - In a large mixing bowl, whisk together the sweetened condensed milk, whole milk, melted butter, granulated sugar, vanilla extract, ground cinnamon, and salt until well blended.
04 - Stir the rinsed rice and optional raisins into the dairy mixture, ensuring everything is evenly incorporated.
05 - Pour the mixture into the prepared baking dish. Gently stir to distribute the rice evenly.
06 - Bake uncovered for 1 hour, gently stirring every 20 minutes to maintain an even texture, until the pudding is set and the surface is lightly golden.
07 - Remove from the oven and let cool slightly. Serve warm or chilled, dusted with additional ground cinnamon if desired.