1. Heat the oven to 425°. Rub the cavity of the chicken with the dried rosemary, 1/4 teaspoon salt, and 1/8 teaspoon pepper and then stuff with the strips of lemon zest and the quartered onion. Twist the wings behind the back of the chicken and tie the legs together. Put the chicken, breast-side up, in a roasting pan. Coat the chicken with the oil and sprinkle it with 1/4 teaspoon of salt, 1/8 teaspoon of pepper, and the 1 tablespoon lemon juice.
2. Roast the chicken until it is just done, 50 to 60 minutes. Transfer the bird to a plate and leave to rest in a warm spot for about 10 minutes.
3. Meanwhile, pour off the fat from the roasting pan. Set the pan over moderate heat and add the water. Bring to a boil, scraping the bottom of the pan to dislodge any brown bits. Boil until reduced to approximately 1/4 cup, about 4 minutes. Add any accumulated juices from the chicken along with the remaining 1/4 teaspoon lemon juice and a pinch each of salt and pepper. Serve the bird with the pan juices.
Menu Suggestions: The simplicity of this chicken means that an almost endless list of accompaniments will work well with it. Among the easiest are vegetables that you can roast in a separate pan alongside the chicken, such as potatoes, squash, asparagus, or fennel. Other good choices include rice, polenta, or mashed potatoes.
Wine Recommendation: A straightforward gulpable red wine will pair best with this aromatic dish. Try a Chianti from the Italian region of Tuscany.