Roasted Chicken with Green Olives, Orange and Lemon

A wonderful Mediterranean flavour to this recipe.  From Food and Drink 2001

One 2.5 kg chicken
2 tbsp butter, melted
3 oranges
1 lemon
1 head garlic
5 sprigs thyme
5 sprigs rosemary
2 tsp herbes de provence
Salt and freshly ground pepper
1/2 cup dry vermouth
18 large pitted green olives, washed
2 tsp cornstarch

1. Preheat oven to 425F.  Wash and dry the chicken, brush with butter and season.  Cut one orange and lemon in half.  Squeeze and reserve juice and halves.  Break garlic into individual cloves.  Place inside chicken with thyme, rosemary and one orange and lemon half.  Tie the legs and tail together and tuck neck flap under the wings.  Sprinkle with herbes de Provence and season.
2. Place chicken on its side in roasting pan, using remaining orange and lemon halves to support it.  Pour juice over chicken, add 1 cup water to pan and roast 20 minutes.  Turn chicken on to other side and roast another 20 minutes.  Turn on to its back, baste and add more water to pan if necessary.  There should always be some liquid at bottom of pan.  Reduce oven temperature to 350F and continue to roast for one to one and a half hours, basting occasionally, until instant read thermometer reads 180F when inserted to thigh.
3. Remove chicken from pan, place breast side down on warmed serving dish.  Cover loosely with foil and place in warm place for 15 minutes.  Skim liquid in roasting pan to remove fat.  Strain into saucepan and add the juice of the two remaining oranges, and vermouth.  Cut olives in half and add to the saucepan.  Bring to boil.  Mix cornstarch with 1 tbsp cold water and whisk into sauce.  Simmer for 5 minutes.
4. Carve chicken and serve with sauce.