Mix the cream cheese with the garlic and the lemon zest.
Loosen the skin on the chicken breasts and spread 2 tablespoons of the cream cheese between the skin and the flesh on each. Press the skin back in place and season it with salt and freshly ground black pepper, oregano and thyme, or herbs of your choice.
Bring a saucepan of water to the boil and cook the leek and parsnip for 4 minutes.
Drain them well, pat dry them with paper kitchen towelling, and place them in a lightly oiled baking dish. Drizzle with oil and season to taste with salt and freshly ground black pepper, oregano and thyme.
Place the chicken on top of the vegetables and put the baking dish in the oven.
Roast for 40 minutes, by which time the skin should be browned and the cream cheese should have melted so that it forms a sauce over the vegetables.
Check that the vegetables are fully cooked and tender by piercing thenm with a skewer. If they need a little longer, cover the dish with aluminium foil and cook for a further 5 minutes. If the chicken is fully cooked, remove it from the baking dish before returning the vegetables to the oven and put it on a serving plate covered with aluminium foil.
Serve with your favourite potato side dish or a simple mash potato dish, and with green vegetables.