In a 6 quart pot, add extra-virgin olive oil. When almost smoking, add the onion and garlic and saute over medium heat until the onions become very soft, about 8 minutes. Add the celery and carrot and saute for 5 minutes. Raise heat to high and add the ground beef. Saute, stirring frequently and breaking up any large lumps and cook until meat is no longer pink, about 8 minutes. Add the tomatoes, parsley and basil and cook over medium low heat until the sauce thickens, about 1/2 hour. Finish bolognese with Pecorino Romano. Check for seasoning.