Original: However , different recipes , even in the Bolognese tradition , make use of chopped pork or pork sausage , while chicken , rabbit , or goose liver may be added along with the beef or veal for special occasions , and today many use both butter and olive oil for cooking the soffritto of small amounts of celery , carrot and onion .
Simplified: In the United States as well , the term bolognese is often applied to a tomato-and-ground-beef sauce that bears little resemblance to ragù served in Bologna .