Pappardelle with Lamb Ragù

Name: Pappardelle with Lamb Ragù
Ingredients: 3 tablespoons extra-virgin olive oil; 1 carrot, finely diced; 1 onion, finely diced; 1 celery rib, finely diced; 1 1/2 pounds ground lamb; 2 teaspoons ground coriander; 1 teaspoon ground fennel seeds; 1/2 teaspoon ground cumin; 1 teaspoon chopped rosemary; 1 teaspoon chopped thyme; Salt and freshly ground pepper; 1 tablespoon tomato paste; 1/2 cup dry red wine; One 28-ounce can diced tomatoes; 1 1/4 cups chicken stock or low-sodium broth; 3/4 pound pappardelle; 1 tablespoon unsalted butter; 3/4 cup fresh ricotta cheese; 2 tablespoons chopped mint