To Make the Stuffing:
Place the bread, parsley, thyme and onion in a food processor. Process until you have fine bread-crumbs and the onion is finely chopped. Season andadd in the butter. Give it another quick whiz then pack the stuffing into the body cavity and fold over any loose skin to close. Secure with a cocktail stick.
To Cook the Chicken:
Set the oven at Gas Mark 6, 200°C (400°F). Place the chicken and vegetables in a roasting tin. Drizzle with the olive oil and season well with the salt and pepper.
Place in the centre of the preheated oven. After the first ten minutes turn the heat down to Gas Mark 4, 180ºC (350ºF).
Roast the chicken for approx. 1 hour 20 mins (allow 20 minutes per 500g plus 20 minutes over).
Halfway through cooking, spoon the juices over the chicken and add a couple of tablespoons of water to the roasting tin to stop the vegetables from burning.
To check if the chicken is cooked pierce the thickest part of the leg - the juices should run clear.
When cooked remove the chicken from the oven, transfer to a carving board and cover loosely with foil. Allow to rest for 10 minutes in a warm place while you make the gravy.
For the gravy:
Strain all but 1 tablesp. of fat from the tin, then sprinkle in a tablesp. of flour. Cook for a couple of minutes and then add in 300-400ml of stock (home-made if possible) and bring to the boil, stirring and scraping to loosen the caramelised meat juices.
Simmer for 2-3 minutes and season to taste. Strain into a gravy boat, discard the vegetables and serve.
Note: To make chicken stock, peel and chop 2 carrots and 1 onion. Place them in a saucepan along with a trimmed and chopped leek and celery stalk if available. Add in a chicken carcass, 2 litres of cold water and a bay leaf. Bring to the boil then reduce the heat and simmer gently for two hours. Strain, check the seasoning, allow to cool and then chill. Skim any fat from the surface of the stock. Freeze when cooled or store in the fridge and use within three days.