Why I Love to Make This Spaghetti Squash Chicken Casserole
Spaghetti squash can be tricky: its tough skin makes it difficult to cut, it needs to roast before the flesh becomes usable, and its strands are mild on their own. This casserole solves those issues. Roasting halved squash on a sheet with chicken breasts results in tender squash that’s easy to scrape into strands, while the chicken cooks alongside and stays juicy. Pan-fried zucchini adds a pleasant caramelized note, and a sauté of onion, bell pepper, garlic and Italian seasoning builds savory depth. Cherry tomatoes and a splash of chicken stock finish the sauce, and frozen peas bring a pop of color and sweetness. Everything is combined with the shredded chicken, topped with mozzarella and Parmesan, then baked until bubbly and golden. The result is a cozy, flavorful casserole that feels familiar yet fresh.
Everything you’ll need to make this recipe.
- Spaghetti squash—a football-shaped squash with pale skin. When roasted the flesh separates into noodle-like strands that provide a lighter base than traditional pasta.
- Zucchini—sliced and sautéed until brown to add texture and flavor. Don’t salt it before browning to avoid releasing moisture.
- Cherry or grape tomatoes—small tomatoes stay sweet and flavorful year-round, especially in winter.
- Italian seasoning—a blend of dried herbs that complements the vegetables and ties the casserole together.
Here’s how to make this recipe.
- Roast the squash and chicken. Trim the ends from each spaghetti squash and slice them in half lengthwise. Scoop out the seeds and pith. Arrange the squash halves cut-side up on a parchment-lined baking sheet and add the chicken breasts to the same sheet. Drizzle with olive oil and season with kosher salt and black pepper. Flip the squash cut-side down and roast at 375°F for 45–60 minutes. The chicken will finish sooner; remove it when an instant-read thermometer reads 160°F. Let the squash cool until you can handle it.
- Brown the zucchini. Slice the zucchini in half lengthwise and cut into 1/4-inch pieces. Heat neutral oil in a skillet and add the zucchini in a single layer. Let each side brown without adding salt so it crisps nicely. Remove when golden and set aside.
- Prepare the tomato mixture. Dice an onion and a bell pepper. In the same skillet, add the onion and bell pepper to the hot oil with salt and sauté until softened. Halve the cherry tomatoes and mince the garlic, then add them to the pan along with Italian seasoning, red pepper flakes, black pepper and chicken stock. Simmer until the tomatoes burst and most of the liquid cooks off, about 8–12 minutes. Remove from heat.
- Scoop out the squash. Use a spoon to scrape the roasted squash flesh into a large bowl and separate it into strands with your hands or a fork.
- Mix everything together. Shred or chop the cooked chicken and add it to the bowl with the spaghetti squash. Stir in the peas, browned zucchini and the tomato mixture. Transfer the mixture to a greased 9×13 baking dish, smooth the top, and sprinkle with mozzarella and Parmesan.
- Bake the casserole. Bake at 375°F for 35–45 minutes, until the casserole is heated through and the cheese is melted and bubbling. If you prefer a browned top, broil for 1 minute at the end. Let rest 10 minutes before serving.
These pro tips will make this recipe a success.
- If your spaghetti squash has small brown spots, cut them away. The squash is fine to use as long as it isn’t extensively discolored.
- A grapefruit spoon or sturdy spoon makes scooping the strands quick and easy.
- Don’t salt zucchini until after it browns; salt draws moisture and prevents a crisp, caramelized exterior.
- For a golden, slightly crisp top, switch the oven to broil for the last minute of baking and watch carefully.
Follow These Tips
Serving
Serve warm straight from the baking dish alongside a fresh green salad or sliced avocado.
Storage
Store in the refrigerator for 7–10 days. Leftovers don’t freeze well because spaghetti squash releases extra moisture when thawed.
Frequently asked questions about this recipe.
Yes. Cook pasta to al dente, toss with a little butter to prevent sticking, and use it in place of the squash.
Yes. Sausage, ground beef, or ground turkey are good alternatives. For a vegetarian version, omit the meat and use vegetable stock.
Yes. Any color bell pepper works; use hot peppers if you prefer more heat.
More casserole recipes you’ll love.
- Three-cheese stuffed shells
- Chicken tortilla casserole
- Ham and cheese egg croissant casserole
- Homemade green bean casserole
- Stuffed acorn squash casserole
- Baked macaroni and cheese
- The best homemade goulash
- Sungold tomato pasta bake
- Chipotle sweet potato taco bake
Have I Convinced You to Make This Recipe?
I hope you try this casserole and enjoy it with family or friends. Leave a comment and a star rating to let others know how it turned out — your feedback helps others decide to try the recipe, too.
Spaghetti Squash Chicken Casserole
Ingredients
For the squash and chicken
- 2 spaghetti squash
- 1 lb chicken breast
- 1 tbsp olive oil
- ¾ tsp kosher salt
- ½ tsp freshly ground 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 freshly ground 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
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Preheat the oven to 375°F.
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Cut stems from the squash, halve lengthwise, and remove seeds. Place squash and chicken on a parchment-lined baking sheet, drizzle with olive oil, season with salt and pepper, turn squash cut-side down, and roast.
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Roast chicken until it reaches 160°F (about 16–20 minutes), then remove. Continue roasting the squash until tender, 45–60 minutes, then cool.
For the casserole
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Grease a 9×13 baking dish and set aside.
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Heat 2 tablespoons neutral oil in a large skillet. Slice zucchini and sauté until browned, 3–4 minutes per side. Remove and set aside.
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Add diced onion and bell pepper to the skillet with salt and cook until softened, 4–6 minutes. Add halved tomatoes, garlic, Italian seasoning, red pepper flakes, black pepper, and chicken stock. Bring to a boil, then simmer until the tomatoes burst and liquid mostly reduces, 8–12 minutes. Remove from heat.
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Scrape the squash strands into a large bowl, add shredded chicken, peas, zucchini and the tomato mixture. Stir to combine and transfer to the prepared baking dish. Top with mozzarella and Parmesan.
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Bake at 375°F until warmed through and cheese is melted, 35–45 minutes. Let cool 10 minutes before serving.
Video
Notes
- If your spaghetti squash has any small brown spots, slice them away. The squash is fine if it isn’t extensively discolored.
- A grapefruit spoon works well for scooping the squash strands.
- To get a crisp exterior on the zucchini, don’t salt it while sautéing; salt draws out moisture and prevents browning.
- For a golden top, broil the casserole for the last minute of baking, watching closely to avoid burning.
Nutrition
Nutrition information is automatically calculated and should be used as an approximation.
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