Leftover Turkey Chili with Cheesy Cornbread Topping

Name: Leftover Turkey Chili with Cheesy Cornbread Topping
Ingredients: 2 tablespoons olive oil; 1 large onion, cut into 1/2-inch pieces; 3 ribs celery, cut into 1/2-inch pieces; 1 leek, white and light green parts only, cut into 1/2-inch pieces; 3 carrots, cut into 1/2-inch pieces; 2 tablespoons tomato paste; 3 tablespoons chile powder; 2 teaspoons paprika; 1 teaspoon ground cumin; 1/4 teaspoon cayenne pepper; 1 tablespoon coarse salt; 3 cups homemade turkey or chicken stock or store-bought low-sodium chicken broth; 1 cup canned crushed tomatoes; 2 cups prepared turkey gravy; 2 pounds shredded cooked turkey; 2 (15.8-ounce) cans black beans, drained and rinsed; Cornbread Batter; 8 tablespoons shredded white cheddar cheese