Macaroni with Bolognese sauce   Ingredients: 4 Tbs. (1/2 stick) unsalted butter 2 Tbs. extra-virgin olive oil 3 thin slices pancetta, finely chopped 1 large yellow onion, cut into small dice 1 carrot, peeled and cut into small dice 1 celery stalk, cut into small dice 1/2 lb. ground beef 1/2 lb. ground pork 1/2