Place the farro into a sieve and rinse with cold water. Drain.
Place the farro into a medium-sized pot with a lid. Add the water or stock or a combination of both, and add the salt and butter or olive oil if using. Bring to a boil over high heat.
Reduce the heat to low, cover, and gently simmer for about 30 minutes, until it is tender but still chewy (if you have soaked it overnight, the cooking time will be shorter). The cooking time depends on a number of factors, all explained above! If there is liquid remaining in the pot, drain it in a sieve.
If you are using it in a salad or a room-temperature dish, spread it out on a rimmed baking sheet to cool to prevent it from getting mushy.
Notes
Rinse and drain your farro before cooking.
You can toast the farro first in a dry pot over medium heat, stirring frequently, for a few minutes to give it an even nuttier flavor before proceeding with the simmering instructions below.
Soaking farro can shorten the cooking time, but it's not necessary.
Use a combo of half water and half chicken or vegetable broth to give your farro an extra bump of flavor.
Farro is not gluten-free, so people with gluten intolerances or celiac should not eat it.