In a large skillet heat the 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 10 minutes. Add the tomatoes, parsley and basil and cook over medium low heat until the sauce thickens. Season with salt and pepper. This will take approximately 1/2 hour. Finish bolognese with Pecorino Romano.
Recipe courtesy of Giada De Laurentiis