Skin the cooked chicken pieces and set aside.
Heat the butter with the oil in a large cast iron or flameproof casserole dish, add the garlic, onions and pancetta and sauté for about 5 minutes until softened. Add the mushrooms and thyme and sauté for 5 minutes.
Pour in the wine, bring to the boil and continue boiling, uncovered, for about 5 minutes until the sauce is reduced by half. Pour in the stock and bring back to the boil.
Season and add the chicken to the sauce. Reduce the heat and simmer for a good 5 minutes until the chicken is thoroughly heated through. Remove the chicken pieces to a warmed serving dish with a slotted spoon.
Increase the heat and boil the sauce until reduced by about half. Reduce the heat, stir in the cream and gently heat through.
Pour the sauce over the chicken pieces, sprinkle with parsley. Serve.