Remove breasts from either side of chicken breast bones using a thin bladed filleting knife and following the shape of the rib cage. Cut across breasts at wings to remove breasts from carcasses. Cut legs and thighs from carcasses through ball and socket joints at thighs. Make pockets in breasts behind fillets and insert a small sage leaf in each. Season chicken pieces. Chop onion and heat with stock in a large pan until boiling. Add chicken legs, reduce heat and simmer gently for 15 minutes. Peel and trim carrots and parsnips, chop into thick slices. Add half the sage and summer savory, prepared carrots, parsnips and chicken breasts to pan. Add a little more stock to cover if necessary. Cook for a further 15 minutes. Remove chicken pieces and half the vegetables from the pan with a slotted spoon. Puree the remainder in a liquidizer or food processor until cold. Rinse pan and return sauce to it through a sieve. Chop the remaining sage and summer savory. Stir in cream and chopped herbs. Season to taste. The texture should be silky and the flavour robust. Trim the leeks into 2 inch pieces. Place the chicken with reserved vegetables and prepared leeks in a roasting tin and pour half the sauce over and around. Roast, uncovered, in pre heated oven for 15 minutes or so, until chicken is cooked and vegetables have a nice golden glaze. Heat remaining sauce. Serve chicken and vegetables with remaining sauce poured round. Garnish with a sprinkling of chopped parsley or chives. DISCLAIMER(c) Copyright 1996 - SelecTV Cable Limited. All rights reserved. Carlton Food Network http://www.cfn.co.uk/