Instructions

• Bring a large pot of salted water to a boil, add the mostaccioli, and cook 2 minutes less than package directions; drain and toss with a little olive oil to prevent sticking.
• Heat olive oil in a large skillet over medium heat, add diced onion with a pinch of salt, and cook until translucent, about 4 to 5 minutes; stir in minced garlic and cook until fragrant, about 30 seconds.
• Add the Italian sausage and cook, breaking it up, until browned and no longer pink; drain excess fat if needed.
• Stir in crushed tomatoes, tomato paste, water or broth, Italian seasoning, red pepper flakes if using, sugar, 1 teaspoon salt, and several grinds of black pepper; simmer 8 to 10 minutes until thickened and glossy, then taste and adjust seasoning.
• In a bowl, combine ricotta, 1 cup mozzarella, and 1/4 cup parmesan; season with a pinch of salt and pepper and stir until creamy.
• Heat the oven to 375°F (190°C) and grease a 9x13-inch baking dish; toss the cooked pasta with about two-thirds of the meat sauce.
• Spread a thin layer of the remaining sauce in the baking dish, layer half the sauced pasta, dollop half the ricotta mixture, and sprinkle with 1 cup mozzarella and 1/4 cup parmesan.
• Repeat with the remaining pasta and ricotta, then top with the rest of the sauce and the remaining mozzarella and parmesan.
• Cover the dish tightly with foil, tenting slightly, and bake for 20 minutes; remove the foil and bake 10 to 15 minutes more until the cheese is bubbly and golden at the edges.
• Let the casserole rest for 10 minutes, finish with chopped basil or parsley, slice, and serve.