Description

This Chicken Alfredo Spaghetti Squash Casserole is a comforting, low-carb twist on classic Alfredo pasta. It features roasted spaghetti squash strands baked in a creamy Alfredo sauce with tender chicken, mozzarella, and Parmesan cheese, creating a rich and satisfying meal. Optional veggies like broccoli and mushrooms add extra flavor and nutrition, making it perfect for a hearty family dinner or meal prep.

Ingredients

Scale

Main Ingredients

2 medium spaghetti squash (about 3–4 pounds total)
3 cups cooked chicken (shredded or diced, such as 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)

Optional Vegetables

1 cup steamed broccoli
1 cup sautéed mushrooms

For Garnish

Fresh parsley or basil (chopped)

If Making Homemade Alfredo Sauce

2 tbsp butter
2 garlic cloves (minced)
1 cup heavy cream
¾ cup grated Parmesan cheese
Salt, pepper, and a pinch of nutmeg (optional)

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Instructions

Prepare the Spaghetti Squash: Preheat your oven to 400°F (200°C). Slice each spaghetti squash in half lengthwise and scoop out the seeds with a spoon. Drizzle the cut sides with olive oil and season with salt and pepper. Place the halves cut-side down on a baking sheet.
Roast the Spaghetti Squash: Bake the squash for 30 to 40 minutes until it is tender and easily pierced with a fork. Remove from the oven and let it cool slightly.
Shred the Squash: Use a fork to scrape out the flesh of the squash into spaghetti-like strands. Set aside in a large mixing bowl.
Prepare the Alfredo Sauce (If Making Homemade): In a saucepan over medium heat, melt 2 tablespoons of butter. Add the minced garlic and sauté until fragrant, about 1-2 minutes. Pour in 1 cup of heavy cream and simmer gently for 3 to 4 minutes. Whisk in ¾ cup grated Parmesan cheese until the sauce is smooth. Season with salt, pepper, and a pinch of nutmeg if desired.
Preheat Oven for Casserole: Lower the oven temperature to 375°F (190°C). Grease a 9×13-inch casserole dish to prevent sticking.
Assemble the Casserole: Spread a thin layer of Alfredo sauce on the bottom of the casserole dish. Layer half of the spaghetti squash strands over the sauce, followed by half of the cooked chicken and half of the Alfredo sauce. Sprinkle a bit of Parmesan cheese over the layer. Repeat these layers with the remaining spaghetti squash, chicken, and Alfredo sauce. Finish by topping the casserole with shredded mozzarella cheese.
Bake the Casserole: Cover the dish with foil and bake for 20 minutes. Then, remove the foil and bake for an additional 10 to 15 minutes, until the cheese is bubbly and golden brown.
Serve: Garnish the casserole with freshly chopped parsley or basil. Serve warm, optionally accompanied by a side salad or roasted vegetables.

Notes

Using a rotisserie chicken is a great time saver, but any cooked chicken works well.
Feel free to add steamed broccoli or sautéed mushrooms into the casserole layers for extra veggies and flavor.
If you prefer a lighter sauce, you can substitute half-and-half for heavy cream in the homemade Alfredo sauce.
To save time, use store-bought Alfredo sauce instead of making your own.
The casserole can be assembled the day before and refrigerated; just add extra baking time if baking straight from the fridge.
Spaghetti squash can vary in size; adjust roasting time accordingly if squash is particularly large or small.