Preheat oven to 375.

In a small bowl, mix 3 tablespoons of the olive oil, garlic, walnuts, rosemary, and parsley.

With your hands, gently loosen the skin on the chicken breast. Spread the walnut mixture evenly under the skin. Quarter the lemon and put it in the body cavity.

Rub the chicken all over with the rest of the olive oil. Put it on a rack in a roasting pan and put it in the oven.

Roast for 1 1/2 to 1 3/4 hours, or until the drumstick moves easily and the juice runs clear when the thigh is pierced to the bone.

Remove the chicken to a platter. Remove the lemon wedges but put them on the platter with the chicken. Let it rest for 10 to 15 minutes before carving.

Carve the chicken and serve with the lemon wedges to squeeze over it.