01 - Preheat the oven to 325°F. Lightly grease a 2-quart baking dish with butter.
02 - Rinse the rice thoroughly under cold water until the water runs clear; drain well.
03 - In a large mixing bowl, whisk together sweetened condensed milk, whole milk, melted butter, sugar, vanilla extract, cinnamon, and salt until fully blended.
04 - Stir the rinsed rice and optional raisins or sultanas into the milk mixture.
05 - Pour the prepared mixture into the greased baking dish and gently stir to ensure even distribution of rice.
06 - Bake uncovered for 1 hour, stirring gently every 20 minutes, until the pudding is set and lightly golden on top.
07 - Remove from the oven and allow to cool slightly. Serve warm or chilled, garnished with extra cinnamon if desired.