Tip - stone the olives with the proper tools so as to leave them undamaged.
Prepare the filling, in the butter and oil fry the veal, pork and chicken breast finishing with the addition of ½ glass of dry marsala, which will evaporate.
Add canned tomato or puree and cook until all meat is tender.
Once cooled, mince the meat and mix into it the pecorino cheese, black truffle, salt and pepper to taste.
Add egg yolks (saving the white for the crumbing stage) until combined. You should get a soft homogeneous mixture.
Stuff the olives with the filling, dip them in the flour and beaten egg white and finally in breadcrumbs.
Fry in boiling oil and serve very hot.