Place in a large bowl the portions of chicken, the chopped vegetables, the mustard, the cheese, the olive oil, the herbs, salt and pepper and mix them well with your hands. Cover the bowl and let it in the refrigerate for 2 hours.
Divide the portions and the vegetables-cheese mixture into the 4 sheets of parchment paper and close them well (if you want, tie them tie with string). Bake them at 180 ° C for about 1h and 15', open them and serve.