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Overhead photo of a baking dish of spaghetti squash casserole

Spaghetti Squash Casserole Recipe

This Spaghetti Squash Casserole with chicken and shredded cheese is the perfect weeknight meal. Made with roasted spaghetti squash, this casserole is easy to make, low carb, gluten-free, and I’ll bet that everyone in your family will be reaching for seconds!
Course dinner, Main Course
Cuisine American
Keyword casserole, Roasted Spaghetti Squash, Spaghetti Squash
Prep Time 15 minutes
Cook Time 1 hour
Total Time 1 hour 15 minutes
Servings 6 people
Calories 367kcal


For the Spaghetti Squash

For the sauce

  • 1 tbsp olive oil
  • ½ cup red onions chopped
  • 2 garlic cloves minced
  • 3 cups cooked shredded chicken breast— skinless
  • 1 cup store-bought spaghetti sauce or homemade tomato sauce
  • 1 ½ cups shredded mozzarella


For the Spaghetti Squash:

  • Preheat oven to 400F.
  • Halve the spaghetti squash with a sharp knife and using a spoon, remove seeds.
  • Pour over olive oil on the inside of the spaghetti squash and season with salt and black pepper to taste.
  • Place spaghetti squash cut-side down on the baking sheet and roast in oven on middle rack for about 40-50 minutes. The time will depend on the size of the spaghetti squash.
  • Remove from oven and let cool slightly.
  • Using a fork, gently remove spaghetti squash strands from the squash and set aside.

For the Sauce

  • In a cast iron skillet 10”, heat olive oil over medium-high heat.
  • Add onions and garlic and cook for about 3 minutes.
  • Add cooked chicken and tomato sauce to the skillet, mix everything together to combine and cook for 1 minute. Add the spaghetti squash strands and mix all to combine.
  • In a casserole dish, place the spaghetti squash/chicken/tomato sauce mixture and top with mozzarella cheese. Bake for 10 minutes or until golden and bubbly.


Serving: 1/6 | Calories: 367kcal | Carbohydrates: 12g | Protein: 42g | Fat: 17g | Saturated Fat: 7g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 7g | Cholesterol: 105mg | Sodium: 1218mg | Potassium: 406mg | Fiber: 4g | Sugar: 7g