This Chicken Spaghetti Casserole is a warm, gently aromatic dish that brings together tender pieces of cooked chicken, long strands of spaghetti, and a velvety, cheese-enriched sauce baked until lightly golden. The aromas are subtle yet comforting: soft sweetness from sautéed onions, depth from garlic, and richness from melted cheese. It is well-suited for everyday cooking, ideal for colder days, and particularly fitting for family meals when something hearty and familiar is desired. The casserole offers both structure and softness in each serving, making it a dependable, nourishing recipe for any home cook.
Servings
Servings: 6–8 servings
Times
Prep Time: 20 minutes
Cook Time: 35 minutes
Total Time: 55 minutes
Ingredient List
Main Ingredients
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350 g dry spaghetti
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450 g cooked chicken breast or thighs, cut into small bite-sized pieces
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1 medium onion (120 g), finely chopped
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3 cloves garlic (9–10 g), minced
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1 tbsp (15 g) unsalted butter
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1 tbsp (15 ml) olive oil
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300 ml chicken broth
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200 ml heavy cream
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180 ml canned diced tomatoes or mild tomato sauce
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250 g shredded cheddar cheese
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120 g shredded mozzarella cheese
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40 g grated Parmesan cheese
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1 tbsp (12 g) all-purpose flour
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1 tsp (5 g) Dijon mustard (optional, for depth)
Spices & Seasoning
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1 tsp (3 g) paprika
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½ tsp (1.5 g) dried oregano
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½ tsp (1.5 g) dried thyme
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½ tsp (1.5 g) onion powder
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½ tsp (1.5 g) garlic powder
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½–1 tsp (3–5 g) fine salt, or to taste
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¼ tsp (1 g) black pepper
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2 tbsp (4–6 g) chopped fresh parsley, for garnish (optional)
Step-by-Step Preparation
1 – Build the Aroma Base
Bring a large pot of salted water to a boil and cook the spaghetti until just shy of al dente; about one minute less than package instructions. Drain and set aside.
Meanwhile, warm the butter and olive oil in a wide sauté pan over medium heat. Add the finely chopped onion and cook gently for 4–5 minutes until soft, translucent, and aromatic. Stir frequently to prevent browning. Add the minced garlic and continue sautéing for 30–45 seconds, allowing its aroma to bloom without letting it darken. This aromatic base will anchor the entire casserole, ensuring depth beneath the creamy surface.
Sprinkle the flour over the onion-garlic mixture and stir to coat evenly. Cook for 1 minute to remove any raw flour notes while maintaining a controlled heat to avoid scorching.
2 – Deglaze & Add Liquid
Slowly pour in the chicken broth while whisking to create a smooth, lightly thickened base. Allow the mixture to loosen any fond from the bottom of the pan, integrating all the cooked flavors into the sauce. Once the broth begins to warm through, add the heavy cream and the tomato component (diced tomatoes or tomato sauce). Stir until the mixture is homogenous, then gently fold in the Dijon mustard if using. The sauce should now appear creamy with a soft rosy hue, ready to receive seasoning and cheese.
Introduce half of the cheddar cheese and half of the mozzarella into the sauce. Stir over low heat until they melt fully and the sauce develops a refined, glossy texture. This step ensures cohesion throughout the casserole and prevents clumping later in the bake.
3 – Season & Simmer
Add the paprika, oregano, thyme, onion powder, garlic powder, salt, and pepper. Allow the sauce to simmer on low for 3–4 minutes, stirring periodically to maintain an even consistency. Taste and adjust seasoning if necessary; the flavors should be balanced but not overly pronounced, leaving room for the topping cheeses to contribute their richness.
Fold the cooked chicken pieces into the sauce, coating them thoroughly. Add the drained spaghetti and mix gently using tongs or a wide spoon, ensuring the sauce distributes evenly through the strands without breaking them.
Transfer the mixture to a lightly greased baking dish. Spread the surface evenly and sprinkle the remaining cheddar and mozzarella over the top, finishing with grated Parmesan for subtle sharpness and enhanced browning.
Bake in a preheated oven at 190°C for 20–25 minutes. The top should melt, bubble, and take on light golden edges. Allow the casserole to rest for at least 5 minutes before serving, as this brief settling period helps the structure stabilize.
4 – Serve
Serve the casserole warm, ideally directly from the baking dish. For a refined presentation, garnish with chopped fresh parsley to add a contrasting freshness against the creamy, baked richness. The dish pairs well with a crisp green salad, steamed vegetables, or roasted seasonal greens. Each portion should offer tender spaghetti, a cohesive cream-based sauce, and a lightly caramelized cheese crust.
Variations
Creamier Version
Increase the heavy cream to 300 ml and add 50 g additional mozzarella for a richer, more velvety sauce.
Vegetarian Option
Replace chicken with sautéed mushrooms, roasted cauliflower, or a mix of spinach and artichokes.
Spicy Casserole
Add ½–1 tsp of crushed red pepper flakes or substitute smoked paprika for subtle heat.
Broth Alternatives
Use vegetable broth or a light homemade stock for a more aromatic, delicate profile.
Cheese Variations
Swap cheddar for Gruyère or Monterey Jack for a different melting character and flavor dimension.
Tips
Avoid Overcooking the Pasta
Slightly undercooking the spaghetti before baking prevents it from becoming overly soft during the final oven stage.
Layered Flavor Development
Take time to slowly sauté the onions and garlic; properly developed aromatics significantly improve the overall balance of the dish.
Prevent Curled Dairy
When adding cream, keep heat moderate and avoid rapid boiling to maintain a smooth sauce texture.
Storage & Freezing
The casserole keeps well refrigerated for up to 3 days. For freezing, cool completely and store tightly sealed for up to 2 months. Reheat gently to preserve creaminess.
Golden Surface Control
If the top browns too quickly, cover loosely with foil; if additional browning is desired, place under a broiler for 1–2 minutes while monitoring closely.
