Drain the rice.

In another pot put in the water, salt and butter. Bring it to a boil. Throw in the rice.

Let it boil until the water is gone. Bring down the temperature to medium or less. Cook for 30 minutes.

For a very crunchy bottom of rice, towards the end add some oil on the sides of the pot. Let it cook for 5 minutes.

To serve, put the serving dish on top of the pot and turn the rice.

The bottom of the rice is called Tadig - the most popular part of Persian cuisine.