Cut a pocket into the chicken breasts and fill with the feta cheese. Season with salt and pepper. Wrap the proscuitto around the chicken and seal the chicken pockets by lightly frying in the olive oil along with the spring onions.
Cut the celery and the leeks and place in a baking dish dish with the butter and a little salt and pepper.
Put the chicken pieces on top of the leeks and celery. Fry the pears and the grated fresh ginger in the oil, chicken juices and spring onions for about 2 minutes and pour over the chicken.
Finally pour the stock over the lot, cover and cook until chicken is tender - 30-40 minutes.
When done, drain the juices into a saucepan, thicken with a little cornflour and drizzle the sauce over the chicken after serving.