Chicken Alfredo Spaghetti Squash Casserole

Roasted spaghetti squash stands in for pasta in this layered casserole, holding up to a homemade Parmesan cream sauce and shredded chicken without turning to mush. Roasting and shredding the squash takes a little patience, but from there it's a straightforward layer-and-bake situation. It's a naturally lower-carb way to get an Alfredo-style dinner on the table.

Roasted spaghetti squash strands are layered with chicken and a homemade Parmesan cream sauce, then baked into a cheesy casserole.

Why You'll Love This Recipe

• Fast: ready in about 70 minutes (20 min prep, 50 min cook)
• Simple: 12 everyday ingredients
• Feeds the family: 6 servings
• Light: about 350 calories per serving

Ingredients

• 2 medium spaghetti squash (about 3–4 pounds total)
• 3 cups cooked chicken (shredded or diced (e.g., rotisserie chicken))
• 2 cups Alfredo sauce (homemade or store-bought)
• 1 cup mozzarella cheese (shredded)
• ½ cup Parmesan cheese (grated)
• 1 tsp garlic powder
• 1 tsp Italian seasoning
• Salt and pepper (to taste)
• 1 tbsp olive oil (for roasting squash)
• Fresh parsley or basil (chopped (optional garnish))
• 1 cup steamed broccoli (optional)
• 1 cup sautéed mushrooms (optional)

Instructions

1. Heat the oven to 400°F (200°C).
2. Slice the spaghetti squash in half lengthwise and scoop out the seeds with a spoon.
3. Drizzle the cut sides with olive oil, sprinkle with salt and pepper, and place them cut-side down on a baking sheet.
4. Roast for 30 to 40 minutes, until the squash is tender and the skin pierces easily with a fork.
5. Let it cool slightly, then scrape out the strands with a fork into a bowl and set aside.
6. Melt 2 tablespoons of butter in a saucepan over medium heat.
7. Add the minced garlic and sauté until fragrant.
8. Stir in the heavy cream and simmer for 3 to 4 minutes.
9. Whisk in the grated Parmesan until smooth.
10. Season the sauce with salt, pepper, and a pinch of nutmeg if using.
11. Heat the oven to 375°F (190°C).
12. Grease a 9x13-inch casserole dish.
13. Spread a thin layer of the Alfredo sauce over the bottom of the dish.
14. Layer in half the spaghetti squash strands, half the chicken, and half the sauce, then sprinkle with Parmesan.
15. Repeat the layers once more, finishing with mozzarella on top.
16. Cover the dish with foil and bake for 20 minutes.
17. Uncover and bake for another 10 to 15 minutes, until the cheese is bubbly and golden.
18. Garnish with fresh parsley or basil and serve warm with a side salad or roasted vegetables.

Cooking Tips

• Roast the squash cut-side down so it steams in its own moisture and cooks evenly.
• Let the roasted squash cool for a few minutes before handling so it's easier to shred.
• Reserve some Parmesan for topping so the casserole gets a golden, bubbly crust.

Substitutions

• Rotisserie chicken can replace freshly cooked chicken for a shortcut.
• Half-and-half can be used in place of heavy cream for a lighter sauce.
• Steamed broccoli or sautéed mushrooms can be layered in for extra vegetables.

Storage

• Refrigerate leftovers in an airtight container for up to 4 days.
• Reheat individual portions in the microwave or the whole dish covered in the oven.
• Freeze baked and cooled portions for up to 2 months.

Serving Suggestions

• Serve with a side salad or roasted vegetables for a complete meal.
• Garnish with fresh parsley or basil right before serving.
• Add a sprinkle of extra Parmesan at the table.

Nutrition (per serving)

Nutrient	Amount
Calories	350 kcal

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