We clean and wash the vegetables. Finely chop the onion and put the celery and carrot on a small grater. Finely chop the greens.
Mix all of the above in a bowl, adding a little salt and 2 teaspoons of olive oil.
Wash the chicken and dab it with a paper towel.
Beat each piece of chicken breast in turn with a meat hammer, placing a cling film on top.
Grease each piece of meat with the vegetable filling and carefully roll and then tie the roll formed with food string.
Place the two pieces of chicken in a small tray and pour two cups of water.
Cover with Al foil. and put in the preheated oven at 185 degrees for 30 minutes.
After 30 minutes, remove the foil and turn the rolls from one side to the other and leave them in the oven for about 20 minutes.
Remove from the oven, cut the string and after it has cooled, slice and serve.