Rinse 1 cup pearled farro under cold running water. In a medium saucepan, combine rinsed farro, 2.5 cups water or broth and 1/2 tsp kosher salt. Bring to a boil, then reduce heat to a simmer. Cover and cook until tender but slightly chewy, about 18–22 minutes for pearled farro. If using semi-pearled or whole farro, adjust time (25–40 minutes).

Drain any excess liquid, fluff with a fork, and spread the cooked farro on a baking sheet or large plate to cool quickly to near room temperature (about 15–20 minutes). Cooling prevents wilting the arugula later.

Pickled Red Onions

Quick-pickle onions

While the farro cooks, place 1 cup thinly sliced red onion in a jar or bowl. In a small saucepan, combine 1/2 cup apple cider vinegar, 1/2 cup water, 1 tbsp sugar and 1/2 tsp kosher salt. Warm over medium heat, stirring until sugar and salt dissolve — you do not need to boil. Pour the warm pickling liquid over the onions, press to submerge, and let sit at room temperature for at least 20 minutes. For best flavor, refrigerate for 1 hour; they keep in the fridge for up to 2 weeks.

Dressing

Whisk dressing

In a small bowl or jar, combine 3 tbsp extra-virgin olive oil, 2 tbsp fresh lemon juice, 1 tsp honey (or maple syrup), 1/2 tsp Dijon mustard, 1/2 tsp kosher salt and 1/4 tsp freshly ground black pepper. Whisk or shake until emulsified. Taste and adjust acidity or sweetness as desired.

Salad Assembly

Combine salad ingredients

In a large mixing bowl, add the cooled farro and 3 cups packed arugula. Add 1.5 cups halved seedless grapes, 1/2 cup coarsely chopped pistachios, and most of the crumbled ricotta salata (reserve a small amount for topping). Drain the pickled red onions and add about half (or to taste) to the bowl — reserve some for garnish.

Dress and toss

Pour about two-thirds of the dressing over the salad and gently toss to combine, making sure the arugula is lightly coated and ingredients are evenly distributed. Taste and add more dressing if needed; season with additional salt and pepper if required.

Transfer the salad to a serving platter or bowl. Top with the remaining ricotta salata, the reserved pickled onions, and the additional 2 tbsp pistachios for crunch. Finish with 1 tsp fresh lemon zest if using.