Cook the farro. Rinse the farro. Fill a medium pot with water. Salt the water to taste and bring it to a boil. Once the water boils, stir in the farro. Reduce the heat and simmer until tender. Cooking time will depend on the type of farro you're using: 10-20 minutes for pearled, 20-30 minutes for semi-pearled, and 40 minutes for whole farro. I used whole farro for this salad. Once cooked, drain the farro and spread it out on a large baking sheet to cool.
Make the dressing. Meanwhile, whisk together the dressing ingredients in a small bowl and set aside.
Assemble the salad. Add the cooled farro to a bowl, and toss it with the apple slices, raisins, shaved cheese, nuts, and arugula. Drizzle the dressing over the salad. Toss the salad to coat it with the dressing. Taste and adjust the seasonings before serving.
Notes
Cooking depends on the type of farro: 10-20 minutes for pearled, 20-30 for semi-pearled, and 40 for whole farro. Or just follow the instructions on the package.
Make sure the farro is cooled before combining it with the fresh arugula, or the arugula will wilt.
You can use dried cranberries or chopped dates instead of raisins.