Beat the vinegar, mustard, lemon juice, garlic, olive oil, salt, black pepper in a small bowl. In the bag (bag) for baking put the chicken pieces and pour the mixture vinaigrette. Close bag, shake and leave in refrigerator to marinate at least 2 hours and up to 1 day. You can do it in the morning and in the evening you return from work to put it to bake. Preheat oven to 200 C. Put the chicken in the bag in the oven slightly riddled bag top. Bake until the chicken is covered with a brown crust - about 1 hour. Remove chicken pieces from the bag. Pour sauce bag in a pan and add the butter, to thicken the sauce and chicken broth. Cook until the mixture boil off and obtain an average thick consistency. Put a piece of chicken on a plate, pour the sauce and sprinkle with grated lemon zest and parsley.