Preheat oven to 425°F. Wash and thoroughly dry the chicken. Sprinkle a generous amount of salt and pepper inside the cavity, then rub the entire bird with olive oil. Sprinkle salt and pepper on the underside o the chicken and place it, breast side up, in a roasting dish. Stuff the cavity with the lemon and onion and generously sprinkle the top with salt and pepper.

Roast the chicken for 1 1/2 hours, basting every 1/2 with the juices that accumulate in the pan. The hickey thigh should register 165°F on a thermometer at the very least (I usually let it go 180 to make sure it's cooked to the bone). Let the chicken rest for at least 10 minutes before carving and eating. After removing the chicken from the oven, be sure to pour about 1/2 cup boiling water into the roasting dish; use a wooden spoon to scrape up all the browned bits from the bottom of the pan and serve the chicken with these rich pan juices.