COMBINE in a bowl the PHILLY, stock, wine, mustard, sage, garlic, and seasonings. Wrap each chicken breast in a piece of prosciutto. Place the chicken in a single layer in a baking dish, with the leeks, and pour over the PHILLY mixture. Sprinkle with cheese
BAKE in a moderate oven 180°C for 30 minutes or until the chicken is cooked. (If the sauce has curdled, a quick whisk will bring it back together again)
