1/2poundwhole-milk mozzarella cheese,cut into small cubes
1cup (8 ounces)ricotta cheese
Place sausage in a Dutch oven and cook over medium-high heat, breaking sausage up with a wooden spoon as it cooks. Once sausage is about halfway cooked, add onion. Cook 2 to 3 more minutes and add garlic. Cook 1 minute.
Add diced tomatoes, tomato sauce, tomato paste, Italian seasoning, sugar, salt, and red pepper flakes. Simmer for 10 minutes.
Add water and ziti. Stir well to get the ziti submerged. Cook 8 to 10 minutes or until pasta is almost al dente. (You still want it fairly firm because it will continue to cook for a while longer.)
Remove Dutch oven from heat. Stir in Parmesan cheese and mozzarella cheese. With a spoon, dollop ricotta cheese on top. Place Dutch oven in oven under the broiler until cheese on top is hot and melted.