1 3.5 to 4 lb whole chicken, backbone removed and butterflied
3 Tbs grated zest plus 1/3 cup lemon juice from 3 lemons
1 tsp sugar
salt and pepper
2 cups low sodium chicken broth
1 cup water
1 tsp corn starch
1 Tbs water
3 Tbs unsalted butter
1 Tbs finely chopped parsley
Adjust oven rack to middle position and preheat to 475. Pat chicken dry with paper towels. Combine lemon zest, sugar, and 1 tsp salt in small bowl. Rub 2 Tbs zest mixture under skin of chicken. Season chicken with salt and pepper and retransfer to roasting pan. Can be refrigerated for 2 hours.
Whisk broth, water, lemon juice and remaining zest and add to roasting pan. Liquid should reach skin of thighs. If not, add water. Roast until skin is golden brown and thighs measure 170 to 175, about 40 to 45 minutes. Transfer chicken to cutting board and let rest 20 minutes
Pour liquid from roasting pan to saucepan, should be about 1 1/2 cups. Skim fat then cook over medium high heat until reduced to about 1 cup. Whisk corn starch with water then whisk into sauce. Simmer until slightly thickened, about 2 minutes. Off heat, whisk in butter and parsley. Season with salt and pepper. Carve chicken and serve, passing sauce at table.
Can also be made with bone-in chicken breasts. Cook them to 160 before resting. Two large breasts will serve 4.