Place the rice into an 8-inch square glass baking dish.
Bring the water, butter, and salt just to a boil in a kettle or covered saucepan. Once the water boils, pour it over the rice, stir to combine, and cover the dish tightly with heavy-duty aluminum foil. Bake on the middle rack of the oven for 1 hour.
After 1 hour, remove cover and fluff the rice with a fork. Serve immediately.