Chicken and grape sauce
Heat the oil in a non-stick pan. Season the chicken, brown over a medium heat for approx. 7 mins. on each side, remove from the pan. Stir fry the onions and sage in the same pan for approx. 3 mins. Add the grapes, cook briefly. Sprinkle with flour. Pour in the port, bring to the boil, reduce slightly, season. Transfer everything to the baking dish, place the chicken on top (skin side up).
To roast in the oven
Approx. 25 mins. in the centre of an oven preheated to 200°C.
Sweet potato mash
Cook the sweet potatoes in salted water for approx. 20 mins. until soft, drain, mash with a fork or potato masher. Combine the oil, sage and salt, mix into the sweet potatoes, serve with the chicken.