01 - Preheat oven to 325°F. Lightly grease a 2-quart baking dish with butter.
02 - Rinse the short-grain rice under cold water until water runs clear, then drain thoroughly.
03 - In a large mixing bowl, whisk together 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 milk mixture until evenly incorporated.
05 - Pour mixture into the prepared baking dish and gently stir to distribute the rice evenly.
06 - Bake uncovered for 1 hour, gently stirring every 20 minutes, until pudding is set and the surface is lightly golden.
07 - Remove from oven, let cool slightly, and serve warm or chilled with extra cinnamon sprinkled on top if desired.