Pork Shank Osso Buco

Name: Pork Shank Osso Buco
Ingredients: 6 pork shanks (7 1/2 pounds; see Note); Kosher salt; Freshly ground black pepper; 3 tablespoons extra-virgin olive oil; 1 large white onion, chopped; 1 large carrot, chopped; 1 celery rib, chopped; 3 garlic cloves, minced; 2 anchovy fillets, minced; 1 tablespoon finely grated lemon zest; 1/2 teaspoon crushed red pepper; 1 cup dry white wine; Two 28-ounce cans crushed tomatoes; 2 cups chicken stock or low-sodium broth; 5 thyme sprigs; 2 rosemary sprigs; 2 bay leaves; Creamy polenta, for serving