The familiar comfort of cheesy pepperoni pizza, reimagined over roasted spaghetti squash with sautéed mushrooms, onions and seasoned ground chicken tossed in pizza sauce. This spaghetti squash pizza casserole is a flavorful, lower-carb twist on traditional pizza that’s perfect for weeknight dinners, meal prep, or a potluck. Below I’ll walk you through how to make it step by step.
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Why This Recipe Works
- All the pizza flavor with fewer carbs and fewer calories. Roasted spaghetti squash replaces traditional crust while retaining the satisfying combo of pizza sauce, melted cheese and pepperoni. Ground chicken, mushrooms, and onions add texture and protein. The dish is naturally gluten free.
- Easy to customize. Swap ground chicken for ground beef, Italian sausage, a vegetarian ground substitute, or omit meat altogether. Add your favorite pizza vegetables — bell peppers, spinach, artichokes — and use whatever pepperoni you prefer.
- Family friendly and practical. This casserole is comforting, nutritious, reheats well, and works great for meal prep or feeding a crowd.
Key Ingredients
- Spaghetti squash — a mild, slightly firm squash that’s low in carbs and calories and provides fiber and nutrients.
- Ground meat — ground chicken keeps the dish lean; substitute any ground meat you like.
- Pizza sauce — I prefer pizza sauce for a more authentic pizza flavor, but marinara works fine too.
- Pepperoni — use your favorite style and size.
- Shredded cheese — mozzarella or an Italian blend melts best; shredding from a block yields the best melt and texture.
How To Cut and Roast A Spaghetti Squash
Begin by trimming both ends of the squash so it sits flat on the cutting board.
Carefully slice the squash in half lengthwise with a sharp knife. Some larger or firmer squash require more effort—take care and go slowly.
Scrape out the seeds and strings with a sturdy spoon. You can discard them or roast the seeds like pumpkin seeds.
Place the halves on a parchment-lined baking sheet, spray or brush with oil, and season with salt and pepper.
Turn the halves flesh-side down, poke a few holes with a fork, and roast at 400°F (200°C) for 35–45 minutes, or until tender when pierced.
Allow the squash to cool until it’s safe to handle, then use a fork to scrape the flesh into spaghetti-like strands. Discard the skins and set the strands aside.
How To Make This Recipe
- Roast the spaghetti squash first, then prepare the filling and assemble the casserole.
Heat the oil in a large skillet over medium-high heat and cook the diced onion until translucent, about 5 minutes.
Add sliced mushrooms and cook another 3–4 minutes until they soften.
Push the vegetables to one side, add a splash of oil if needed, and brown the ground chicken with Italian seasoning, salt and pepper. Cook until no longer pink, then combine with the vegetables.
Drain excess liquid from the pan, create a small well, add the minced garlic and cook briefly until fragrant, about 1 minute.
Stir in the pizza sauce, bring to a gentle simmer and cook a few minutes to combine flavors.
Fold in the shredded spaghetti squash until everything is evenly combined.
Transfer the mixture to a lightly oiled baking dish in an even layer.
Top evenly with shredded cheese.
Arrange pepperoni over the cheese and bake in a preheated 375°F (190°C) oven for 20–25 minutes, until the top is golden and bubbly. Optionally broil briefly (1–3 minutes) for extra browning.
Remove from the oven, let the casserole rest 5–10 minutes, garnish with fresh basil, and serve warm. Enjoy!
Frequently Asked Questions
My casserole is a little soupy — how can I fix it?
- Spaghetti squash can hold water. To reduce excess moisture, place the cooked shredded squash in a colander and press gently with a spoon to drain some liquid before mixing with the sauce.
What should I serve with it?
- This casserole pairs well with a crisp side salad or a piece of crusty bread if you want extra carbs.
Tips
- Watch the squash closely. Smaller squash cook faster; 35–40 minutes is typical but ovens vary.
- Let it rest. Allow the baked casserole to sit 5–10 minutes to firm up before serving.
- Make it spicy. Add red pepper flakes, spicy sausage, or hot pepperoni to increase heat.
- Storage. Store leftovers in an airtight container in the refrigerator for up to 4 days.
Recipe Summary
Spaghetti Squash Pizza Casserole
Ingredients
- 1 spaghetti squash
- spray cooking oil
- salt and black pepper, to taste
- 1 tablespoon olive or avocado oil
- ½ yellow onion, diced
- 3 cloves garlic, minced
- 8–10 sliced mushrooms (about 1½ cups)
- 1 pound ground chicken (or preferred ground meat)
- 1 teaspoon Italian seasoning
- 1¼ cups pizza sauce (or marinara)
- 1 cup shredded Italian four-cheese blend or mozzarella
- 8–10 pepperoni slices
- Fresh basil, chopped or chiffonade, for garnish
Instructions
Prepare and Roast the Spaghetti Squash
- Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.
- Trim the ends of the squash and carefully slice it in half lengthwise.
- Use a sturdy spoon to remove seeds and strings.
- Place halves flesh-side up, spray with cooking oil, season with salt and pepper, then turn flesh-side down and poke a few holes with a fork.
- Roast 35–45 minutes, until tender when pierced. Let cool, then scrape the flesh into strands and discard skins.
Make the Casserole
- Reduce the oven to 375°F (190°C).
- Heat oil in a large skillet over medium-high. Add diced onion and cook until translucent, about 5 minutes.
- Add mushrooms and cook 3–4 minutes more.
- Push vegetables to the side, add a little more oil, and brown the ground chicken with Italian seasoning, salt and pepper. Mix with the vegetables and cook a few minutes until cooked through.
- Drain excess liquid, add garlic to the pan and cook 1 minute.
- Stir in pizza sauce and simmer 3–4 minutes.
- Add the shredded spaghetti squash and combine evenly.
- Transfer the mixture to a lightly oiled baking dish in a single layer. Sprinkle with shredded cheese and arrange pepperoni on top.
- Bake 20–25 minutes until cheese is bubbly and golden. Let rest 5–10 minutes, garnish with basil, and serve.
Notes
- Pepperoni: Use as many or as few slices as you like; larger slices will cover more surface.
- Stubborn squash: If the squash is very firm, poke holes in the skin and microwave it 2–4 minutes to soften slightly before cutting.
- The nutrition values are approximate and will vary with ingredient brands and portion sizes.
Nutrition
Calories: 276.9 kcal |
Carbohydrates: 17 g |
Protein: 21.1 g |
Fat: 13.6 g
About Priscilla Lawrence
Hi, I’m Priscilla Lawrence. Welcome to Sprinkled With Balance, where I share approachable, nutrient-rich recipes that are simple and satisfying. I’m a recipe developer, former certified nutritionist, and food photographer based in California.