The comfort of a cheesy pepperoni pizza, but on top of delicious and nutritious roasted spaghetti squash, sautéed mushrooms, onions, ground chicken mixed with pizza sauce! This spaghetti squash pizza casserole is such a fun and surprising dish the whole family will love! Let me guide you on how to make it.
Why This Recipe Works
- This recipe is so delicious, low carb and significantly lower in calories that a traditional pizza but with all its flavors! Pepperoni, pizza sauce, melted cheese is added to a roasted spaghetti squash mixed with ground chicken, mushrooms, onion and spices. And it's gluten free!
- It's customizable to your taste! While I chose mushrooms and chicken, because I love this combo like in this Dijon chicken and ground chicken stir fry, you can absolutely use ground beef, ground Italian sausage, vegetarian meat substitute or no meat at all. You could also use bell peppers, spinach, artichokes or any veggies you love on pizza. Same with the pepperoni, use any kind you prefer.
- This pizza casserole is comforting, nutritious, kid-friendly and great for meal-prep. It's also a fun dish to bring to potluck or make for a gathering.
- Spaghetti Squash: this nutritious squash is low carb, low calorie, a good source of fiber and filled with vitamins and minerals as you can read more about it here. The texture has a little bite to it and it's pretty mild tasting.
- Ground meat: I used ground chicken for added lean protein, but you can use any ground meat you love the most.
- Pizza sauce: I prefer pizza sauce for this recipe over marinara sauce because its seasoning is different and taste more like a pizza than just tomato sauce to me, but you can absolutely use marinara sauce if it's what you have on hand.
- Pepperoni: use your favorite ones. These are the ones I used.
- Shredded cheese: I used a pre-shredded pack of Italian four cheese mix, but shredded mozzarella works great too. Even better, shredding your own cheese from a block will melt really well, and make the spaghetti squash pizza casserole super cheesy.
How To Cut and Roast A Spaghetti Squash
First cut the ends of the squash.
Then carefully slice the squash in half lengthwise with a sharp knife.
Scrape the seeds and gut out with a sturdy spoon, and discard (or you can roast them like pumpkin seeds).
Place the halves onto a parchment lined baking sheet, spray them with some cooking oil and season with salt and pepper.
Turn the halves around and poke a few holes with a fork. Roast in preheated oven at 400°F for 35 to 45 minutes. It's ready once the squash feels tender when poked with a fork or knife.
Carefully turn around (it'll be very hot), let it sit for a bit until it's comfortable enough to handle, then shred the inside by scraping with a fork. Discard of the skin.
How To Make This Recipe
- Roast the spaghetti squash first then cook the remaining ingredients.
Heat oil, then cook the onion for 5 minutes.
Then add the mushrooms and cook 3-4 more minutes.
Add the chicken, Italian seasoning, salt and pepper and cook for about 5 minutes.
Remove the excess liquid, add the garlic and cook for 1 minute.
Add the pizza sauce, bring to a low boil.
Mix in the shredded spaghetti squash.
Add the mixture to a baking dish on a single layer.
Sprinkle with cheese.
Add the pepperoni. Then add to preheated oven at 375°F. Bake for 20 to 25 minutes.
Remove from the oven, let cool for 5 to 10 minutes and serve. Enjoy!
More Delicious Squash Recipes To Try
- Air Fryer Butternut Squash
- Chicken Zucchini Boats
- Air Fryer Delicata Squash
- Cheesy Zucchini Casserole
- Butternut Squash Leek Soup
Frequently Asked Questions
My spaghetti squash casserole is a little soupy, how can I fix it?
- Spaghetti squash is a little watery and will make this casserole juicy. While it's not mandatory, you can add an extra quick step by adding the cooked shredded squash in a colander, and gently pressing on it with a wooden spoon to discard of extra liquid.
What can I serve this dish with?
- This recipe is great served with a crunchy side salad, a little sourdough if you want extra carbs.
- Don't overcook the spaghetti squash. The smaller the squash the fastest it'll cook and vise-versa. 35-40 minutes is usually the sweet spot but it might need a few extra minutes depending on your oven too.
- Make sure to let the casserole rest for 5 to 10 minutes before serving.
- You can definitely make this dish spicier by adding some red pepper flakes, use spicy sausage meat or extra spicy pepperoni.
- Leftovers can be stored refrigerated in an airtight container for up to 4 days.
Spaghetti Squash Pizza Casserole
- sharp knife
- spoon & fork
- wooden spoon
- baking dish 10.5x7.5 or 13x9
- 1 spaghetti squash
- spray cooking oil
- salt to taste
- black pepper to taste
- 1 tablespoon olive oil or avocado oil
- ½ yellow onion diced
- 3 cloves garlic minced
- 8-10 sliced mushrooms about 1 ½ cup
- 1 pound ground chicken
- 1 teaspoon Italian seasoning
- 1 ¼ cup pizza sauce or marinara sauce
- 1 cup shredded Italian four cheese medley or shredded mozzarella
- 8-10 pepperoni slices
- basil chopped or slice in chiffonade
Prepare and Roast the Spaghetti Squash
- Preheat oven to 400° Fahrenheit. Line a small to medium baking sheet with parchment paper to cook the squash.
- Carefully cut each ends of the spaghetti squash with a sharp knife.
- Then cut the spaghetti squash in half lengthwise. Some spaghetti squash are firm and this step might require a little muscle. Be careful. *see notes
- With a study spoon, scrape out all the seeds from the middle.
- Place the two halves of the squash on the prepared baking sheet flesh side up, spray each half with a little spray cooking oil, then sprinkle salt and black pepper.
- Turn each halves of the squash around, putting the flesh down, and carefully poke a few holes all around with a fork. Add to preheated oven, and cook for 35 to 45 minutes or until the squash is tender when poked with a fork or knife. (*the smaller the squash the quicker it'll cook and vise-versa).
- While the squash is cooking, finely dice the onion, mince the garlic and slice the mushrooms.
- Once the squash is cooked, remove it from the oven, very carefully turn it around (it'll be really hot), then let it sit for a few minutes until it's cooled down enough to handle. Using a fork, shred the spaghetti squash into strands by simply scrapping the flesh. Set aside and discard of the outer part of the squash.
Make the Casserole
- Reduce the oven to 375° Fahrenheit.
- Heat up the oil in a large skillet over high heat, then swirl the skillet around to coat with oil, then reduce heat to medium high and add the onion. Cook until translucent, stirring often about 5 minutes.
- Add the slice mushrooms and cook them down for about 3 to 4 minutes, stirring often.
- Then push the onion and mushrooms to one side of the skillet, add a tad more oil on the empty side, and add the ground chicken. Add the Italian seasoning, salt and black pepper to it, mix it in and brown the chicken for 2 minutes alone. Then mix it with the onion and mushrooms, and cook for 3-5 minutes.
- Drain any extra liquid from the skillet using a large spoon to scoop it out, or by tilting the skillet over a bowl to discard the liquid. Then make a little space in the middle and add garlic. Cook until fragrant, about 1 minute.
- Add the pizza sauce to the skillet, stir it in and bring to low boil and simmer for about 3-4 minutes.
- Then add the cooked shredded spaghetti squash to the skillet.
- Lightly spray the baking sheet with spray cooking oil, then add the chicken and squash mixture onto one layer.
- Then sprinkle the shredded cheese all over.
- Add the pepperoni slices and bake for 20 to 25 minutes or until the top is golden brown and bubbly. (*optional: broil at the very end for 2 to 3 minutes)
- Remove from oven, let sit for 5 to 10 minutes, sprinkle with some fresh basil, then serve warm by itself or a side salad. Enjoy!
- Pepperoni: I used large pepperoni slices but if you use smaller ones, use as many as you wish.
- Cutting spaghetti squash in half: if your squash is very firm and hard to cut, poke a few holes on the outside all around with a fork, and add the squash to the microwave for 2-4 minutes to soften it and make it easier to cut.