Sausage Casserole

This recipe is from The All New Good Housekeeping Cookbook

Polenta and Sausage Casserole

Layers of creamy polenta, cheese, and a tomato-sausage sauce make this a terrific casserole for a potluck party, buffet, or brunch. Prep: 1 hour Bake: 35 minutes

8 ounces sweet Italian-sausage links, casings removed
8 ounces hot Italian-sausage links, casings removed
1 tablespoon olive oil
1 large onion (12 ounces), chopped
1 large stalk celery, chopped
1 carrot, peeled and chopped
1 can (28 ounces) plum tomatoes in puree
2 cups yellow cornmeal
1 can (14.5 ounces) chicken broth [we use duck broth]
3/4 teaspoon salt
4.5 cups boiling water
1/2 cup freshly grated Permesan cheese
8 ounces fontina or mozzarella cheese, shredded (2 cups) [we use farm-fresh goatzarella]
1. Prepare tomato-sausage sauce: In nonreactive 5-quart Dutch oven, cook sweet and hot sausage meat over medium-high heat, breaking up meat with side of spoon, until browned. With slotted spoon, transfer meat to bowl. discard fat from Dutch oven. 
2. Add oil to Dutch oven. Add onion, celery, and carrot and cook over medium-high heat until browned. Stir in sausage and tomatoes with their puree, breaking up tomatoes with side of spoon. Heat to boiling over high heat. Reduce heat; cover and simmer 10 minutes. Remove cover and simmer 10 minutes longer. 
3. Preheat oven to 350F. Prepare polenta: In 4-quart saucepan with wire shisk, mix cornmeal, broth, and salt. Over medium-high heat, add boiling water and cook, whisking constantly, until mixture has thickened, about 5 minutes. Whisk in Parmesan. 
4. Grease 13″ by 9″ baking dish. Evenly spread half of polenta mixture in baking dish; top with half of tomato-sausage sauce, then half of fontina. Repeat with remaining polenta mixture and sauce. 
5. Bake casserole 15 minutes. Sprinkle with remaining Fontina; bake until mixture is bubbling and cheese is golden, about 20 minutes longer. Let stand 15 minutes for easier serving. Makes 8 main-dish servings.