Method:
Cook the onions in a pan of boiling water for five minutes, then add the sage leaves and continue to boil for a further minute. Drain well and place into a food processor. Add the breadcrumbs, butter, egg yolk, nutmeg, salt and freshly ground black pepper. Blend until the mixture is just combined and resembles large breadcrumbs (do not blend to a paste).
Divide the mix into 10 equal amounts and roll into balls. Place on a greaseproof baking tray ready to bake.
Place the rapeseed oil, chicken fond and chicken breasts in a bowl. Tumble to coat the breasts in the mix.
Lay the chicken onto a lined baking tray. Place the chicken and stuffing balls into an oven preheated to 180°C/350F/Gas 4 and bake for 20 minutes, or until the chicken reaches a core temperature of at least 75°C or above.
To make the gravy, heat 380ml of water in a pan. In a separate bowl mix the gravy powder with the cold water to form a smooth paste. Whisk the paste and the remaining chicken fond into the boiling water and simmer for 3-4 minutes.
Serve one chicken breast and one stuffing ball per person, with a jug of gravy to coat.