Heat 6 tbsp of oil in a large pan. Dip the chicken into the flour and fry until golden on both sides about 10 mins. Remove with a slotted spoon and set aside. Add remaining oil and fry onions, celery and carrot for 5 mins. add mushrooms and cook for a couple of mins more.
Pour in the stock and wine bring to a good bubble, reduce the heat and simmer for 10 mins. return the chicken to the pan, season with salt, pepper and nutmeg.
Just before serving take pan OFF the heat and whisk in egg mixture to thicken sauce. Return to heat briefly, whisking continuously. Taste and season again if required, sprinkle with parsley and serve with rice, pasta or potatoes.