Preheat the oven to 180 °C, 170°C fan assisted, Gas mark 4.
Heat the oil in a frying pan, and fry chicken and onions for 3-4 minutes until browned. Place in an ovenproof casserole dish with the carrots.
Blend the contents of the sachet with the water and add to the casserole. Cover and cook for 1 hour, ensure chicken is thoroughly cooked.
Enjoy with baked potatoes and seasonal vegetables.