1 c. onion, finely chopped
3 tbsp. olive or pure vegetable oil
2 (6 oz.) cans tomato paste
1 (1 lb. 13 oz.) can Italian plum tomatoes
4 c. water
1 tsp. salt
1/2 tsp. pepper
1 bay leaf
1/2 tsp. oregano

Saute onion in hot oil until soft; add tomato paste, tomatoes and water. Stir well. Add seasonings; cover and simmer 1 hour, stirring occasionally. While sauce is cooking, cook rigatoni in 5-quarts boiling salted water for 10 minutes. Drain. Rinse with cold water; drain well.

FILLING:

2 lbs. hot Italian sausage (may use 1/2 regular and 1/2 hot)
1 1/2 c. dry bread crumbs
2/3 c. milk
2 eggs
2/3 c. grated Parmesan cheese

Remove casing from sausage; break up meat and brown well. Add bread crumbs, milk and egg; mix well. Stuff each rigatoni with filling. Layer sauce and rigatoni into large casserole (11x13-inch pan). Sprinkle with cheese. Bake at 350 degrees for 35-45 minutes.