Add the rice to a medium pot. Add hot water to your pot, until the water is two inches higher than the grains.
Place your pot on the stove over high heat. Add the salt to the water and stir it in with a slotted spoon. Cover the pot until it boils. (Mine takes 8 minutes.)
When the water is boiling, remove the lid and lower the heat until the pot is simmering. Simmer the rice, stirring occasionally, until it's al dente (firm but easy to chew). Mine takes 8 minutes. Taste it to see if it's done to your liking. There will be excess water in your pot.
When the rice is cooked, drain the water from the pot into a colander in your sink.
Transfer the cooked rice back to your pot and stir in the butter.
Serve immediately or store leftovers in the refrigerator for up to 5 days. You also can freeze the rice. Press it flat in a plastic freezer bag. When you're ready to use it, use a spoon to break up a section of the frozen rice and scoop out as much as you need. Thaw it in the microwave.
Video
Notes
Use white, long-grain rice, such as Uncle Ben's Original. I haven't tested cooking times and water amounts for other types of rice, so don't substitute brown rice here.If making smaller or larger quantities of rice, always make sure the water in your pot is two inches higher than your grains.