Barbara Lynch's Tagliatelle Bolognese

INGREDIENTS

• 1/4 cup extra-virgin olive oil
• 1 pound coarsely ground pork shoulder
• 1 pound coarsely ground veal
• 1 pound coarsely ground lamb
• 1/2 pound chicken livers, finely chopped
• 1/2 cup minced fresh sage leaves
• 1 large onion, finely diced
• 2 stalks celery, finely diced
• 2 large carrots, finely diced
• 1 bottle dry red wine
• 2 cups chicken stock
• 2 cups veal stock (you can use all chicken if you'd like)
• 1 (28-ounce) can whole peeled italian tomatoes, drained and squeezed between your fingers into medium-sized chunks (liquid reserved)
• 1/2 cup chopped fresh basil leaves
• 1/2 cup chopped fresh parsley leaves
• 4 tablespoons butter
• 2 cups heavy cream
• Kosher salt and freshly gound black pepper
• Torn basil leaves and Parmigiano-Reggiano to finish