1 pound ground Italian sausage (or beef), cooked and drained of fat
2 cups mozzarella, grated
1 (15 oz) container ricotta cheese
1 cup parmesan cheese
1 egg, lightly beaten
1/4 cup water
2 tablespoons olive oil
Salt and pepper, to taste
Preheat oven to 400º F and lightly grease a 9-inch springform pan with nonstick spray. Cook rigatoni noodles in a large pot of salted, boiling water until just al dente (slightly firmer noodles will be easier to work with).
Drain noodles and transfer to a large bowl. Toss with 1-2 tablespoons olive oil, then add parmesan and toss until evenly coated.
In a separate bowl, stir together ricotta, egg, salt, and pepper until thoroughly combined, and set aside.
In a large skillet over medium-high heat, add marinara sauce and water, and heat to a simmer. Stir in Italian sausage, reduce heat to low and let simmer for about 15 minutes.
In the springform pan, stand rigatoni noodles up on one end, making sure to fill any gaps with noodles, but don’t overcrowd.
Pour the ricotta mixture over the noodles and spread it evenly, then add the meaty marinara sauce on top. Gently squish the cheese and meat down into the hollow spaces.
Place springform pan in oven and bake for 15 minutes, then top with mozzarella and bake for another 15 minutes.
Let cool for about 10 minutes, then remove the edge of the springform pan; use a knife to loosen the edges if necessary.