How to Make It
Preheat the oven to 450°. Set racks in the middle and lower thirds of the oven. Rub the chicken all over with
2 tablespoons of the olive oil and season with salt and
pepper. In a large cast-iron skillet, melt the butter. Add
the sage sprigs, then add the chicken, skin side down, and cook over moderately high heat until golden, about 5 minutes. Turn the chicken over and roast in the middle of the oven for about 40 minutes, basting occasionally, until cooked through. Transfer the chicken to a cutting board and let rest for 10 minutes. Reserve the pan juices but discard the sage.
While the chicken is cooking, on a rimmed baking sheet,
toss the carrots and mushrooms with the remaining 3 tablespoons of olive oil; season with salt and pepper. Roast the vegetables on the lower rack of the oven until golden and tender, about 20 minutes. Let cool slightly, then slice the carrots. Transfer the carrots and
mushrooms to a large bowl.
Meanwhile, in a medium saucepan of salted boiling water, cook the farro until al dente, 15 to 20 minutes. Drain well. Add the farro to the vegetables along with the lemon juice,
half of the hazelnuts and 1/2 cup of the reserved chicken pan juices; mix well. Transfer to plates, top with the remaining hazelnuts and garnish with parsley. Carve the chicken and serve it with the farro and lemon wedges.