To prepare the filling, heat the chicken and pork mince with two tablespoons of oil, salt and pepper in a large frying pan over high heat. Turn continuously and when cooked, mince the meat with a knife together with the ham, then transfer to a plate and add the pecorino cheese and a little nutmeg.
Add the eggs to the flour and knead the mixture for about ten minutes, first with a fork and then by hand, until it is smooth and homogeneous. Let the dough rest and in the meantime prepare the broth: in a saucepan put the water with the carrot, celery stalk and onion cut into pieces, and let it cook for about two and a half hours, skimming when necessary. Take the dough and roll it out with a rolling pin, then leave it to rest for half an hour. Then cut the dough with a round cutter, place a ball of filling in the centre of each shape and close in a half-moon shape by joining the tips, according to the typical cappelletti shape. Cook the cappelletti in plenty of broth and serve piping hot.