Tomato, Pasta and Potato Bake

Preheat oven to 400 degrees. Lightly oil a 9-by-13-inch baking dish.

Bring water to a boil and remove from heat.

Arrange half the rigatoni in a single layer in the baking dish. Top with one third the tomatoes, 1 tablespoon oregano, half the potatoes, all the onion and 1/2 cup Parmesan. Season with salt and pepper. Layer with remaining pasta, another third of tomatoes, remaining oregano and potatoes. Season with salt and pepper. Top with remaining tomatoes.

Place dish on rimmed baking sheet. Carefully pour hot water into dish until it comes to the top layer of potatoes. Tightly cover with foil and bake until liquid is absorbed and pasta and potatoes are tender, about 1 hour. Remove foil and sprinkle with remaining Parmesan. Bake until browned, about 20 minutes. Let stand 10 minutes before serving.