Table of Contents
  1. Why this recipe works.
  2. Everything you’ll need to make this recipe.
  3. Here’s how to make this recipe.
  4. These pro tips will make this recipe a success.
  5. Frequently asked questions about this recipe.
  6. More casserole recipes you'll love.
  7. Watch how to make this recipe.
  8. Have I convinced you to make this recipe?
  9. Spaghetti Squash Chicken Casserole Recipe

Instead of stuffing each spaghetti squash with a filling, this casserole incorporates everything into one easy baking dish. A combination of spaghetti squash, tomatoes, zucchini, and chicken are all mixed together and topped with cheese. Once baked, it’s the perfect, hearty meal for a weeknight or special occasion!

Why this recipe works.

Spaghetti squash has a few hurdles to overcome. First, the skin is tough and can be hard to slice through. Second, the squash must be baked in the oven before the noodle-like interior is ready to use. Last, the interior does not have an abundance of flavor. The answer is this casserole. Roasting the halved squash alongside chicken breasts in the oven creates a tender interior that can be easily scraped out. Layers of flavor are added with pan-fried zucchini, sautéed onion with pepper, and Italian seasoning. All ingredients are mixed together with tomatoes and peas the casserole is topped with cheese and baked in the oven until the cheese is bubbling. The result is a flavorful casserole. All the cozy casserole flavors with a fresh take.

White oval baking dish filled with baked spaghetti squash chicken casserole with vegetables sitting in space from spoonful removed.

Everything you’ll need to make this recipe.

  • Spaghetti squash is football-shaped with white-yellow skin. Once they bake, the interior flesh becomes tender. The flesh is spaghetti-sized tender squash.
  • Zucchini can take on a new flavor when sautéed in oil until brown. Make sure to add no salt until it is brown. Salt brings out moisture and inhibits browning.
  • Cherry tomatoes will have a much better taste than larger tomatoes during the winter months. The smaller tomatoes are always sweet and ripe.
  • Italian seasoning is a blend of dried herbs that compliment the vegetables and add a perfect flavor to the casserole.
White marble surface filled with ingredients needed to make a casserole including spaghetti squash, bell pepper, peas, zucchini, onion, chicken, spices, and more.

Here’s how to make this recipe.

  1. Roast the squash and chicken. Slice the ends off of each spaghetti squash, then slice in half. Scoop out the interior seeds and pith and discard. Place each half of squash face up on a parchment-lined baking sheet. Also place the chicken breasts on the parchment. Drizzle the squash and chicken with olive oil, salt, and black pepper. Then flip the squash over so the interior cavity is facing down. Place the pan in the preheated 375°F oven and bake for 45 to 60 minutes. The chicken will cook faster than the squash, so remove the breasts when they reach 160°F. When the squash has finished roasting, remove it from the oven and set aside to cool.
  1. Brown the zucchini. Slice the zucchini in half lengthwise, then cut into ¼-inch thick pieces. In a skillet with hot oil, add each piece of zucchini. Let the zucchini cook, then flip once browned. Let the other side brown, then remove the zucchini from the skillet.
  1. Prepare the tomato mixture. Chop an onion and bell pepper into a fine dice. Add these two ingredients to the hot oil in the skillet along with salt and mix to incorporate. Cut the cherry tomatoes in half and mince up the garlic. When the onion and bell pepper mixture has softened, add in the tomatoes and garlic. Also add the black pepper, red pepper flakes, Italian seasoning, and chicken stock. Stir everything together and let the mixture sauté. When the tomatoes have softened, remove it from the heat. The tomato mixture will likely have some liquid remaining in the pan, which is to be expected.
  1. Scoop out the squash. In a large bowl, use a spoon to scoop out the interior flesh of each half of spaghetti squash. Then break up the flesh using your hand or a spoon.
  1. Mix everything together. Slice or shred the cooked chicken breasts once they cool slightly. Add the chicken to the bowl with the spaghetti squash along with the peas, cooked zucchini, and tomato mixture. Mix everything together and pour into a greased 9×13 baking dish. Smooth out the top and sprinkle with the mozzarella cheese and Parmesan cheese.
  1. Bake the casserole. Place the baking dish in the preheated 375°F oven and bake for 35 to 45 minutes until the cheese has melted and the mixture has warmed through. Remove it from the oven and serve immediately.

These pro tips will make this recipe a success.

  • If your spaghetti squash has any brown spots, simply slice them out. As long as the entire squash is not brown or discolored, it can be used, especially as the squash will be scooped out into strings.
  • When scooping out the interior of each spaghetti squash, a grapefruit spoon works perfectly!
  • To achieve a perfectly crisp exterior to the zucchini, do not add salt while sautéing. Salt will draw out moisture while it’s cooking, which is not desirable as it will not create a crispy crust. Without salt, the zucchini will end up crisp and flavorful.
  • If you want the top of the casserole to be slightly browned and golden, turn on the broiler in the last minute of baking. This blast of heat will darken the cheese on top and add a bit of extra crispness.
Hand holding spoonful of spaghetti squash chicken casserole with all ingredients showing including zucchini, peas, squash, and chicken.

Frequently asked questions about this recipe.

Can regular pasta noodles be used in place of the spaghetti squash?

Yes, spaghetti cooked to al dente can be used in place of the spaghetti squash. Toss butter with the spaghetti noodles before mixing with the ingredients.

Would a different type of meat work well in place of the chicken?

Sausage, ground beef, or ground turkey will work in place of the chicken. For a vegetarian option, use vegetarian stock and leave the meat out completely.

Can any color bell pepper be used in this recipe?

Yes, any color bell pepper can be used. Or for more spice, hot peppers can also be used.

How long does this recipe last once baked?

As leftovers, the casserole will last for 7-10 days in the refrigerator. The leftovers will not freeze well as spaghetti squash draws out too much moisture when frozen.

Watch how to make this recipe.

Have I convinced you to make this recipe?

I hope you make this recipe and put some food on your table. Leave a comment and share a star rating so you can let others know how much you love this recipe. This helps show others that this is a recipe they, too, can make, enjoy, and love!

White oval baking dish filled with baked spaghetti squash chicken casserole on white marble surface with melted cheese over the top.

Spaghetti Squash Chicken Casserole

5 from 4 votes
Instead of stuffing each spaghetti squash with a filling, this casserole incorporates everything into one easy baking dish. A combination of spaghetti squash, tomatoes, zucchini, and chicken are all mixed together and topped with cheese. Once baked, it’s the perfect, hearty meal for a weeknight or special occasion!
Prep Time 15 minutes
Cook Time 1 hour 45 minutes
Total Time 2 hours
Servings 12 servings

Ingredients

For the squash and chicken

  • 2 spaghetti squash
  • 1 lb chicken breast
  • 1 tbsp olive oil
  • ¾ tsp kosher salt
  • ½ tsp black pepper

For the casserole

  • 2 tbsp neutral oil
  • 1 small zucchini
  • 1 medium onion diced
  • 1 bell pepper diced
  • ½ tsp kosher salt
  • 1 pint grape or cherry tomatoes halved
  • 4 cloves garlic minced
  • 1 ½ tbsp Italian seasoning
  • ¼ tsp red pepper flakes
  • ½ tsp black pepper
  • ¼ cup chicken stock
  • 1 cup frozen peas
  • 1 ½ cups shredded mozzarella cheese
  • ½ cup grated Parmesan cheese

Instructions
 

For the squash and chicken

  • Preheat the oven to 375°F.
  • Cut the stems off of the squash, slice in half lengthwise, and remove the seeds and pith. Set the squash cut-side up on a parchment-lined baking sheet along with the chicken breasts. Drizzle everything with olive oil. Sprinkle with salt and black pepper. Turn the squash cut-side down and place the baking sheet in the preheated oven.
    2 spaghetti squash, 1 lb chicken breast, 1 tbsp olive oil, ¾ tsp kosher salt, ½ tsp black pepper
  • Roast the chicken breasts until they register 160°F. The chicken will finish before the squash, so remove them as soon as they are at 160°F, 16-20 minutes.
  • When the squash are darkened on their skin and a knife easily is inserted into the flesh, remove them from the oven, 45-60 minutes. Set the squash aside to cool.

For the casserole

  • Grease a 9×13 baking dish and set it aside.
  • Heat 2 tablespoons neutral oil in a large skillet. Cut the zucchini in half lengthwise and slice into ¼-inch thick pieces. Add the sliced zucchini to the hot oil and sauté until they are browned, 3-4 minutes. Turn the slices over and brown, 2-3 minutes. Once browned, remove the zucchini from the skillet and set them aside.
    1 small zucchini, 2 tbsp neutral oil
  • Add the onion, bell pepper, and salt to the hot skillet. Sauté until the onion is soft and translucent, 4-6 minutes. Add the halved tomatoes, garlic, Italian seasoning, red pepper flakes, black pepper, and chicken stock. Stir to combine and bring the mixture to a boil. Once boiling, turn the heat down to a simmer. Cook until the tomatoes are burst, and the liquid is mostly cooked off, 8-12 minutes. Once cooked, remove the skillet from the heat.
    1 medium onion, 1 bell pepper, ½ tsp kosher salt, 1 pint grape or cherry tomatoes, 4 cloves garlic, 1 ½ tbsp Italian seasoning, ¼ tsp red pepper flakes, ½ tsp black pepper, ¼ cup chicken stock
  • Scrape the flesh of the cooled squash into a large bowl. Shred or chop the chicken into bite-size pieces and add the chicken to the squash. Pour on the peas, zucchini, and prepared tomato mixture. Stir the mixture together and pour it into the prepared baking dish. Sprinkle with mozzarella cheese and Parmesan cheese.
    1 cup frozen peas, 1 ½ cups shredded mozzarella cheese, ½ cup grated Parmesan cheese
  • Bake in the 375°F oven until the casserole is warmed through and the cheese is melted, 35-45 minutes. Once baked, remove the casserole from the oven and cool for 10 minutes before serving.

Notes

  • If your spaghetti squash has any brown spots, simply slice them out. As long as the entire squash is not brown or discolored, it can be used, especially as the squash will be scooped out into strings.
  • When scooping out the interior of each spaghetti squash, a grapefruit spoon works perfectly!
  • To achieve a perfectly crisp exterior to the zucchini, do not add salt while sautéing. Salt will draw out moisture while it’s cooking, which is not desirable as it will not create a crispy crust. Without salt, the zucchini will end up crisp and flavorful.
  • If you want the top of the casserole to be slightly browned and golden, turn on the broiler in the last minute of baking. This blast of heat will darken the cheese on top and add a bit of extra crispness.

Nutrition

Serving: 1servingCalories: 204kcal
Course Dinner
Cuisine American
Difficulty Intermediate
Method Baking

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Kaleb

I’m Kaleb! I'm not a chef, professional baker, landscaper, or designer, but I like to play each on Knollgate Farm. Come join me on my journey and let's learn together!

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3 Comments

  1. 5 stars
    This is so good, I made it over the weekend a couple of weeks ago and shared the recipe with family and friends. Healthy and yummy.

  2. 5 stars
    I will be making this again despite a few user error mistakes. Every once in awhile there would be a bitter taste and I am wondering if that would be the zucchini? Undercooked?
    I also made the roasted carrot and sweet potato soup. Home run!

  3. This recipe is yummy and quite healthy. I only used one spaghetti squash, as it was large. I really appreciate the way the recipe is written with ingredients after each significant step.