Pasta 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 lb. ground veal
• Salt and freshly ground pepper, to taste
• Freshly grated nutmeg, to taste
• 1/2 cup dry white wine
• 2 cups unsalted beef stock or canned broth
• 2 large tomatoes, peeled, seeded and finely chopped
• 5 fresh sage leaves
• 1 bay leaf
• 1/3 cup heavy cream
• 1/4 cup veal demi-glace
• 1 lb. homemade tagliatelle (see related recipe at left) or purchased fresh fettuccine
• 1 cup grated Parmigiano-Reggiano cheese