Season the chicken pieces all over with salt and pepper then set aside.
Heat a touch of oil and the butter in a large pan over a medium heat. When the butter starts to bubble, add the chicken skin-side downwards and sear for 10 minutes, until golden brown and crispy. Remove the chicken from the pan and set aside.
Pour a good dash of olive oil into a large roasting dish. Add all the vegetables, including the smashed garlic bulb, season with salt and pepper, and add the rosemary sprigs and lemon quarters. Place the chicken on top.
Roast for 50 minutes, until the chicken and vegetables are cooked through, then allow to rest for 10 minutes and finish with the chopped parsley.
To serve, take the roasting dish to the table and allow everyone to help themselves.