Rinse: Rinse the rice in cold water in a strainer for 15 to 20 seconds, then shake it dry. (Here’s why to rinse rice.)
Simmer covered: Place the water in a pot and bring to a boil. Add the rice and salt, bring back to a boil, then reduce the heat to low and cover. Simmer for 12 to 15 minutes, until the water is completely absorbed (test by pulling back the rice with a fork). Remove from the heat.
Rest, then season: Cover and rest for 10 minutes (this allows the rice to steam and firm up in texture). Stir in the salt, and the butter or olive oil if using. Taste and add more salt if needed.