1. Season the chicken evenly on both sides with salt and black pepper and fry the chicken pieces in olive oil and butter in a large heavy skillet or dutch oven until they are golden on both sides. Don’t be tempted to lift the chicken until it has been cooking over medium heat for at least 2 minutes a side or it will stick. Use tongs to lift and turn the chicken so you don’t pierce it and lose valuable juices.
2. Lift the chicken pieces out of the pan and remove to a plate. Add the Dijon mustard and crème fraiche to the pan and use a wooden spoon to scrape up the bits from the end of the pan. These are important for flavour. Add the wine and stir. Return the chicken to the pan, put the lid on and braise it slowly over a low heat for 35-40 minutes, checking twice during cooking that there is enough liquid in the pan. If not, add a little water or white wine or a mixture of both to top it up.
3. When the chicken is cooked and just falling off the bone remove it to a warm dish, pour on the sauce and serve.