2	tablespoons (30 ml) olive oil

4	medium carrots, finely chopped

2	large ribs celery, finely chopped

4	medium onions, finely chopped

2	pounds (960 g) chicken sausage with sun-dried tomatoes or nonfat turkey sausage

1	pound (480 g) fresh mushrooms, wiped clean and sliced thin

1	teaspoon crushed dried rosemary

1	cup (240 ml) low-sodium canned beef broth

1	6-ounce (180 g) can tomato paste

1 1/2

cups (360 ml) water

4	28-ounce (793 g) cans no-salt-added crushed tomatoes

2	pounds ziti

3	cups (360 g) shredded nonfat mozzarella cheese

1/2	cup (40 g) freshly grated Parmesan cheese

1. Preheat oven to 350° F ( 180° C), gas mark 4.
2. Heat the oil in a heavy pot. Add the carrot, celery, and onion. Sauté for 10 minutes over medium low heat until the onion is very soft. Turn the heat up and add the sausage meat and cook, breaking up into bite size pieces, until cooked through. Add the mushrooms and rosemary. Cook for 1 minute. Stir in the beef broth and raise the heat, reducing the liquid by half. Add the tomato paste and water. Bring to a slow simmer and cook 1 hour. Add the tomatoes.
3. Cook ziti to al dente, according to package directions. Drain well, reserving 1 cup of the pasta cooking water. Add the pasta water to the sauce. Toss the pasta with the sauce.
4. In each of two 3-quart or larger casseroles, place 1/6 of the pasta. Top each with 1/2 cup (60 g) of the mozzarella cheese. Repeat these layers twice. Sprinkle each casserole with 1/4 cup (20 g) Parmesan cheese.
5. Cover each casserole with aluminum foil and bake for 40 minutes. Remove the foil and bake another 5 to 10 minutes, or until cheese is melted and browned.