1. Preheat the oven to 400°F.

2. Season the chicken inside and out with salt and pepper. Truss it and brush with 2 tablespoons of the olive oil. Place on a rack in a roasting pan and roast until browned but only about half-cooked, about 40 minutes.

3. Meanwhile, in a small bowl, combine the ¼ cup black pepper, a pinch of salt, and the mustard and stir well. Drizzle in 1 tablespoon of the olive oil, whisking until blended.

4. Remove the browned chicken from the oven and brush with the black pepper and mustard mixture. Return to the oven and continue roasting until the juices run clear when a thigh is pricked, about another 30 minutes. Let rest for 10 minutes.

5. While the chicken rests, in a medium bowl, combine the parsley, onion, tomatoes, the remaining 3 tablespoons olive oil, the vinegar, and salt and pepper to taste and toss well.

6. Carve the chicken and arrange on serving plates. Drizzle with the pan juices and the spicy oil, top with the parsley salad, and serve immediately.