Preheat the oven to 190ºC/ Fan 170ºC/Gas Mark 5. Wash the potatoes and quarter. Peel the carrot and parsnip and cut into batons. Place all the vegetables together with the oil in a small roasting dish.
Lay the chicken breast on top of the veg, then roast for 25 minutes or until the chicken is cooked through and the vegetables are tender.
Remove the tray from the oven, transfer the chicken to a plate to cool. Mix the peas with the other vegetables and return to the oven for 5 minutes to heat through.
Heat the gravy in a small pan until hot. Remove the skin from the chicken, then slice into strips, add the vegetables and pour over the gravy. Cool slightly until cool enough to handle.
Try different vegetables for variety e.g. broccoli, cabbage or swede