Roast the carrots: Preheat the oven to 425°F (220°C). Peel the carrots and cut them on the diagonal into 1/4-inch thick pieces. Toss with 2 tablespoons olive oil and 1 teaspoon salt. Spread evenly on a baking sheet and roast for 45 minutes, until tender and lightly caramelized.
Prepare the farro: Bring a large pot of well-salted water to a boil. Once the water is boiling, add the farro and cook for 30–35 minutes, until tender. Drain and briefly rinse under cold water. The farro should be warm, not hot, when added to the salad.
Prepare the dressing and aromatics: In a large mixing bowl, combine the chopped dates, thinly sliced red onion, jalapeños, cilantro, lemon juice, 3 tablespoons olive oil, and 1 teaspoon salt. Stir well and let sit while the carrots and farro cook-this will help soften the onions and meld the flavors.
Assemble the salad: When the roasted carrots have cooled for about 10 minutes (still warm, not hot), add them to the bowl along with the warm farro. Add the chopped Castelvetrano olives and crumbled feta cheese. Toss gently until all ingredients are evenly combined and coated with the dressing.
Serve: Serve immediately while slightly warm, or refrigerate for at least an hour to allow the flavors to develop. This salad tastes even better the next day once the ingredients have fully marinated.