In a large heavy casserole pot, add the butter and olive oil.
When the butter has melted add the pancetta pieces and fry until crisp.
Add the garlic and onion and fry until soft.
Remove and set aside.
Brown the chicken thighs and legs on all sides in the same pot and then add the mushrooms, white wine, garlic, onions and pancetta.
Bring to the boil and simmer over a low heat for 20-25 minutes.
Turn the chicken legs halfway through the cooking time and remove any fat or scum that rises to the top.
When the chicken is cooked remove from the pot and set aside.
Stir the cream into the juices, add a pinch of sea salt and black pepper and simmer for a further 10 minutes or until the sauce is has become a little thicker.