This is the casserole I’ve been making for my family since my children were small. It’s the ultimate comfort food—tender chicken, perfectly sauced pasta, and that glorious golden cheese crust that everyone fights over. It’s simple to assemble, feeds a crowd, and the leftovers (if there are any) taste even better the next day.

Back in my day, this was our go-to for Sunday supper after church. The magic is in the layers: al dente spaghetti soaks up the savory marinara, while tender chunks of chicken provide hearty protein. A blanket of melted mozzarella and Parmesan creates a creamy, golden crust that’s simply irresistible. For the best texture, I always use a heavy, enameled cast iron baker—it holds heat beautifully and gives you that perfect bake. It’s a no-fuss, satisfying dish that proves simple ingredients, treated with care, are always the best.

Ingredients

• 250g spaghetti
• 2 large boneless, skinless chicken breasts (about 400g), cut into 1-inch pieces
• 2 tbsp olive oil
• 1 medium yellow onion, finely diced
• 3 cloves garlic, minced
• 2 cups (480ml) marinara sauce (homemade or good-quality store-bought)
• 1/2 cup (120ml) low-sodium chicken broth
• 1 tsp dried oregano
• 1/2 tsp dried basil
• 1/4 tsp red pepper flakes (optional)
• 1 cup (100g) shredded mozzarella cheese
• 1/2 cup (50g) freshly grated Parmesan cheese
• Salt and freshly ground black pepper to taste
• 1 tbsp unsalted butter (for greasing dish)

Instructions

1. Preheat your oven to 375°F (190°C). Generously butter a 9×13 inch (23×33 cm) baking dish with the tablespoon of butter and set aside.
2. Bring a large pot of well-salted water to a rolling boil. Add the spaghetti and cook according to package directions until *al dente* (typically 8-10 minutes). Reserve 1 cup of the starchy pasta water before draining. Drain the spaghetti and set aside.
3. While the pasta cooks, heat the olive oil in a large skillet or Dutch oven over medium-high heat. Season the chicken pieces generously with salt and pepper. Add them to the hot skillet in a single layer and cook, stirring occasionally, until golden brown and cooked through, about 6-8 minutes. Remove the chicken with a slotted spoon and set aside on a plate.
4. In the same skillet (with the delicious chicken fond), reduce the heat to medium. Add the diced onion and cook until softened and translucent, about 4-5 minutes. Add the minced garlic and cook for another 30 seconds until fragrant.
5. Pour in the marinara sauce and chicken broth. Stir in the dried oregano, basil, and red pepper flakes (if using). Bring the mixture to a simmer and let it cook for 5 minutes to allow the flavors to meld.
6. Add the drained spaghetti and cooked chicken to the sauce in the skillet. Toss everything together gently until the pasta is well coated. If the sauce seems too thick, add a splash of the reserved pasta water, 1/4 cup at a time, until it reaches a creamy consistency that will moisten the casserole.
7. Transfer the entire chicken and pasta mixture into your prepared baking dish, spreading it into an even layer. Sprinkle the shredded mozzarella and grated Parmesan cheese evenly over the top.
8. Bake, uncovered, for 20-25 minutes, or until the cheese is melted, bubbly, and has developed a beautiful golden-brown crust. Let the casserole rest for 5-10 minutes before serving to allow it to set.