Place breast side down with the legs towards you. Using a sharp knife or strong kitchen scissors, cut along each side of the backbone from the Parson’s nose to the neck and remove it carefully. Turn the chicken back over and press down with both hands to flatten.
Alternatively ask your local butcher to do this for you.
1. Preheat the oven to 200°C/180°C fan/gas 6.
2. Peel and halve the onions and place in the bottom of a roasting tin or casserole dish.
3. Prepare the chicken according to taste (we like to add a small amount of butter to the skin and simply season with salt, pepper and thyme) and place on top of the onions.
4. Add water to a depth of 1cm to the bottom of the tin/dish.
5. Cover the chicken with parchment (not foil) and tuck it in around and under the chicken.
6. Surround the covered chicken with the carrots, leeks and potatoes.
7. Cook the chicken for 1 hour, or until the juices run clear.
8. Once the chicken is cooked, remove the parchment, increase the oven temperature to 220°C/200°C fan/gas 7.
9. Cook for a further 5 minutes, or until the chicken and vegetables are golden brown.
10. Remove from the oven, re-cover with the parchment and rest for 15 minutes before serving.