Spaghetti Squash Casserole is the perfect dish when you’re craving something cozy yet light. It combines the natural sweetness of roasted spaghetti squash with rich tomato sauce, gooey melted cheese, and aromatic herbs. Every bite delivers that comforting, cheesy goodness while keeping things on the healthier side. The spaghetti-like strands of squash mimic traditional pasta but with fewer carbs and more nutrients, making it an excellent alternative for those looking to enjoy a wholesome meal without sacrificing flavor.

What makes this casserole so special is its versatility. Whether you’re preparing it for a family dinner, meal prep, or a gathering with friends, it fits seamlessly into any occasion. Plus, it’s easy to customize—add protein like chicken or ground turkey, mix in extra vegetables, or adjust the cheese to your liking. The combination of roasted squash, tangy marinara, and golden-brown cheese creates a dish that’s both satisfying and nutritious.

Why You’ll Love This Spaghetti Squash Casserole

Healthier Alternative – Enjoy all the flavors of a baked pasta dish with lower carbs and extra fiber.
Rich and Comforting – The melted cheese and savory tomato sauce make this a feel-good meal.
Customizable – Add meats, extra veggies, or different cheeses to suit your preferences.
Perfect for Meal Prep – Make it ahead of time and enjoy leftovers that reheat beautifully.
Gluten-Free Option – Naturally gluten-free and easy to make dairy-free with simple substitutions.

Preparation Phase & Tools to Use

Before diving into this delicious Spaghetti Squash Casserole, having the right tools will make the process much easier. Here’s what you’ll need and why each tool is essential:

Sharp Chef’s Knife & Cutting Board – Spaghetti squash has a tough outer shell, so a sturdy knife is crucial for safely cutting it in half.
Spoon or Ice Cream Scoop – Helps remove the seeds and fibrous center of the squash effortlessly.
Baking Sheet & Parchment Paper – Roasting the squash on a baking sheet ensures even cooking and enhances its natural sweetness.
Fork – Used to scrape the roasted squash into spaghetti-like strands.
Large Skillet or Saucepan – Necessary for preparing the tomato-based sauce with seasonings and protein (if using).
Mixing Bowl – Helps in combining the ingredients before layering them into the casserole dish.
9×13-inch Baking Dish – The perfect size for assembling and baking the casserole to golden perfection.
Oven Mitts – Essential for safely handling hot baking dishes.

Preparation Tips

Easier Squash Cutting Tip: Microwave the whole spaghetti squash for about 3–5 minutes before cutting. This softens the skin and makes slicing safer.
Perfect Roasting Technique: Brush the cut sides with olive oil, season lightly, and place them cut-side down on a baking sheet. This helps caramelize the edges for better flavor.
Drain Excess Moisture: Once you shred the squash into strands, pat them with a paper towel to remove excess water. This prevents a watery casserole.
Layering for Maximum Flavor: Mix the squash with the sauce before assembling to ensure every bite is packed with flavor.
Golden Cheese Perfection: Broil the casserole for the last few minutes to get a beautifully golden, bubbly cheese topping.

Ingredients for This Spaghetti Squash Casserole

To create this comforting and flavorful dish, you’ll need a combination of fresh vegetables, rich tomato sauce, and gooey melted cheese. Here’s everything required:

For the Spaghetti Squash:

1 large spaghetti squash (about 3–4 lbs)
1 tablespoon olive oil
Salt and black pepper, to taste

For the Sauce:

1 tablespoon olive oil
1 small onion, diced
3 cloves garlic, minced
1 pound ground turkey, chicken, or Italian sausage (optional)
1 (24-ounce) jar of marinara or tomato sauce
1 teaspoon dried oregano
1 teaspoon dried basil
½ teaspoon red pepper flakes (optional, for a little heat)
Salt and black pepper, to taste

For the Casserole:

1 cup ricotta cheese or cottage cheese
½ cup grated Parmesan cheese
2 cups shredded mozzarella cheese
¼ cup chopped fresh basil or parsley (for garnish)

This ingredient list keeps things simple yet flavorful. Feel free to tweak it based on dietary needs or preferences, such as using dairy-free cheese or adding extra vegetables like spinach or mushrooms.

Step 1: Roast the Spaghetti Squash

Preheat your oven to 400°F (200°C).
Carefully slice the spaghetti squash in half lengthwise and scoop out the seeds with a spoon.
Brush the inside of each half with olive oil and season with salt and pepper.
Place the squash halves cut-side down on a baking sheet lined with parchment paper.
Roast for 35–40 minutes or until the squash is fork-tender.
Let it cool for a few minutes, then use a fork to scrape out the spaghetti-like strands into a large bowl. Set aside.

Step 2: Prepare the Sauce

Heat 1 tablespoon olive oil in a large skillet over medium heat.
Add the diced onion and sauté until softened, about 3–4 minutes.
Stir in the garlic and cook for another 30 seconds until fragrant.
If using ground turkey, chicken, or sausage, add it now and cook until browned, breaking it apart as it cooks.
Pour in the marinara sauce and add oregano, basil, red pepper flakes, salt, and pepper.
Let the sauce simmer for 5–7 minutes, stirring occasionally.

Step 3: Mix and Assemble

In a large mixing bowl, combine the spaghetti squash strands with the prepared sauce. Stir well to coat the squash evenly.
Add ricotta (or cottage cheese) and grated Parmesan, mixing until fully combined.

Step 4: Bake the Casserole

Preheat the oven to 375°F (190°C) if it has cooled down.
Lightly grease a 9×13-inch baking dish and spread the spaghetti squash mixture evenly.
Sprinkle the top with shredded mozzarella cheese.
Bake uncovered for 20–25 minutes, or until the cheese is melted and bubbly.

Step 5: Broil for a Golden Crust

Switch the oven to broil and cook for 2–3 minutes until the cheese turns golden brown.
Keep an eye on it to prevent burning.

Step 6: Garnish and Serve

Remove the casserole from the oven and let it rest for 5 minutes before serving.
Sprinkle with freshly chopped basil or parsley for extra flavor.
Serve hot and enjoy!

Notes

Make it Vegetarian: Skip the ground meat and add sautéed mushrooms, spinach, or bell peppers for extra texture and flavor.
Dairy-Free Option: Use dairy-free ricotta and mozzarella to make this dish completely dairy-free.
Protein Boost: Add cooked shredded chicken or a plant-based protein for a more filling meal.
Make Ahead: You can assemble the casserole ahead of time and store it in the fridge for up to 24 hours before baking.

Watch Out for These Mistakes While Cooking

Not Draining Excess Moisture from the Squash – Spaghetti squash naturally contains water. After shredding, pat it dry with paper towels to prevent a watery casserole.
Overcooking the Squash – Roasting for too long can make the squash mushy instead of maintaining its spaghetti-like texture. Check for doneness at 35 minutes.
Skipping Seasoning – The squash itself is mild, so seasoning it before mixing with the sauce enhances the overall flavor.
Using Too Much Sauce – A light coating is enough; too much sauce can make the dish soggy.
Not Letting It Rest – Allowing the casserole to sit for a few minutes after baking helps the flavors meld and makes serving easier.

What to Serve With Spaghetti Squash Casserole?

Spaghetti Squash Casserole is a hearty dish on its own, but pairing it with complementary sides can make the meal even more enjoyable.

8 Delicious Side Dish Ideas

1. Garlic Bread

A crispy, buttery slice of garlic bread is the perfect way to soak up any leftover sauce from the casserole.

2. Mixed Green Salad

A fresh salad with arugula, spinach, or romaine, dressed in balsamic vinaigrette, adds a refreshing contrast.

3. Roasted Vegetables

Oven-roasted zucchini, bell peppers, or Brussels sprouts add extra nutrition and a delightful caramelized flavor.

4. Steamed Broccoli or Green Beans

Lightly steamed greens with a squeeze of lemon balance out the richness of the casserole.

5. Cauliflower Rice

For an extra low-carb option, serve the casserole with herbed cauliflower rice for a complete meal.

6. Minestrone Soup

A warm bowl of minestrone or tomato basil soup pairs well for a cozy, comforting dinner.

7. Antipasto Platter

A small plate of olives, cured meats, cheeses, and marinated vegetables makes for a tasty Italian-inspired side.

8. Sautéed Mushrooms

Earthy mushrooms cooked in garlic butter bring an umami depth that complements the casserole beautifully.

Storage Instructions

Refrigeration

Let the casserole cool completely before storing.
Place leftovers in an airtight container and refrigerate for up to 4 days.
Reheat individual portions in the microwave for 1–2 minutes or warm the entire casserole in the oven at 350°F (175°C) for 15–20 minutes.

Freezing

Unbaked Casserole: Assemble the dish in a freezer-safe container, cover tightly, and freeze for up to 3 months. When ready to bake, thaw in the refrigerator overnight and bake as directed.
Baked Casserole: Let it cool completely, then slice into portions. Wrap each portion in plastic wrap and store in a freezer-safe container for up to 3 months. Reheat from frozen at 350°F (175°C) for 25–30 minutes.

Estimated Nutrition (Per Serving)

(Approximate values, depending on ingredients used)

Calories: 250–300 kcal
Protein: 15–20g
Carbohydrates: 20–25g
Fiber: 5g
Fat: 12–15g
Sodium: 500–700mg

For a lower-calorie option, reduce the cheese or use low-fat alternatives.

Frequently Asked Questions

1. Can I make this casserole ahead of time?

Yes! Assemble the casserole and store it in the fridge for up to 24 hours before baking. When ready, bake as directed, adding an extra 5–10 minutes to the baking time if needed.

2. How do I make it more filling?

You can add cooked ground turkey, chicken, sausage, or extra vegetables like mushrooms, bell peppers, or spinach for added bulk and flavor.

3. Can I use a different type of cheese?

Absolutely! While mozzarella and Parmesan work well, you can substitute with cheddar, provolone, or even dairy-free cheese alternatives.

4. Is spaghetti squash casserole keto-friendly?

Yes! Spaghetti squash is a low-carb alternative to pasta, making this dish a great option for a keto diet. Just ensure your marinara sauce is low in sugar.

5. Can I freeze leftovers?

Yes! You can freeze individual portions or the entire casserole for up to 3 months. Thaw overnight in the fridge before reheating.

6. How do I keep my casserole from being watery?

After roasting the squash, pat the strands dry with paper towels to remove excess moisture before mixing them into the casserole.

7. Can I add protein to this dish?

Yes! Ground turkey, chicken, sausage, or even shredded rotisserie chicken make great protein additions.

8. What can I use instead of spaghetti squash?

If spaghetti squash isn’t available, try zucchini noodles, butternut squash, or shredded cabbage for a similar texture.

Conclusion

Spaghetti Squash Casserole is a comforting, nutritious, and versatile dish perfect for any occasion. Whether you’re looking for a low-carb dinner, a meal-prep-friendly recipe, or a healthier take on baked pasta, this dish has you covered. With its creamy cheese topping, flavorful sauce, and tender squash strands, it’s a meal that satisfies without feeling heavy. Try it today and enjoy a delicious, guilt-free comfort food experience!