Name: Spaghetti Squash Pizza Casserole Recipe
Prep time: 15 min
Cook time: 30 min
Total time: 45 min
Cuisine: Italian-American
Ingredients: 3 cups pre-cooked spaghetti squash; 1 cup pasta sauce (your preferred variety); 1 ½ cups shredded mozzarella cheese; 1 cup pre-cooked meat (e.g., sausage, ground beef, or chicken); ½ cup chopped mushrooms; ¼ cup sliced olives; ½ cup chopped veggies (e.g., bell peppers, onions, or spinach); 1 teaspoon Italian seasoning; ¼ cup grated parmesan cheese

Jump to Recipe· 3.9 from 34 reviews

If you’re craving the comforting flavors of pizza but want a lighter, veggie-packed twist, this Spaghetti Squash Pizza Casserole Recipe is an absolute game changer. It takes the classic elements you love from pizza—melty cheese, rich sauce, and hearty toppings—and builds them into a warm, cozy casserole brimming with the naturally sweet, tender strands of spaghetti squash. Whether you’re looking for a weeknight dinner or a dish to impress friends without the fuss, this casserole delivers all the deliciousness with simple ingredients and easy steps. Trust me, once you try this Spaghetti Squash Pizza Casserole Recipe, it might just become your new favorite way to enjoy pizza night!

Ingredients You’ll Need

The image shows a white bowl filled with chunky red tomato sauce placed in the center on a white marbled surface. To the right and slightly behind it is another white bowl full of shredded white cheese. In front and to the left of the tomato sauce bowl is a small white dish with golden olive oil. Three beige garlic cloves are laid on the surface between the olive oil dish and the tomato sauce bowl. In the background, two large, yellow spaghetti squashes with smooth, peeling skin rest next to a bunch of fresh, dark green leafy spinach. The light is bright and natural, making the colors of the vegetables and ingredients clear and vivid. Photo taken with an iphone --ar 4:5 --v 7

Gathering the right ingredients is the first step to achieving that perfect balance of comfort and freshness in this dish. Each item brings something unique to the table, whether it’s the vibrant red of the pasta sauce, the gooey goodness of mozzarella cheese, or the subtle earthiness from your choice of add-ins that elevate the casserole’s flavor and texture.

Pre-cooked spaghetti squash: The star of the show—you can cook it easily in the Instant Pot for a quick, tender base.
Pasta sauce: Pick your favorite kind; it adds depth and a tangy tomato punch that ties everything together.
Mozzarella cheese: Provides that irresistible melty, stretchy texture that screams pizza.
Optional add-ins: From pre-cooked meats to chopped mushrooms, olives, or veggies, these personalize the casserole with extra flavor and texture.
Italian seasoning: A sprinkle brings classic herbs like oregano and basil that lift the dish beautifully.
Parmesan cheese: For a nutty, sharp finish sprinkled on top before baking.

How to Make Spaghetti Squash Pizza Casserole Recipe

Step 1: Preheat and Prepare

Start by preheating your oven to 350 degrees Fahrenheit. This moderate temperature ensures that the casserole cooks evenly without drying out, giving your cheese the perfect melting and bubbling opportunity.

Step 2: Assemble the Base

Place your pre-cooked spaghetti squash into a 9×9 inch baking dish—or a larger one if you’re making extra portions. The squash acts as a light, vegetable-packed pasta alternative, adding both substance and a subtle sweetness to your casserole.

Step 3: Add Sauce and Mix-ins

Next, stir in your pasta sauce thoroughly with the spaghetti squash to evenly coat every strand. This step infuses the dish with those classic pizza flavors. If you’re using any meats, mushrooms, olives, or chopped veggies, fold them in now to distribute their deliciousness throughout the casserole.

Step 4: Cheese It Up

Sprinkle a generous layer of mozzarella over the top, and if you’re feeling fancy, add some parmesan for extra richness. The cheese not only adds fantastic flavor but also creates that irresistible golden crust once baked.

Step 5: Bake to Perfection

Pop your dish into the oven and bake for about 30 minutes, until the cheese is beautifully melty and bubbly, and the casserole is heated through. For those who love a crispy cheese topping, switch your oven to broil for 3 to 5 minutes at the end—just keep an eye on it so nothing burns!

How to Serve Spaghetti Squash Pizza Casserole Recipe

A close-up view of a baked dish in a clear glass rectangular baking dish with a white marbled surface underneath. The dish has one thick layer of melted yellow-orange cheese mixed with orange tomato sauce, showing some smooth and slightly bubbly texture. Fresh green basil leaves are placed evenly on top, adding bright contrast to the warm colors beneath. The edges of the dish have a bit of slightly browned sauce, showing it was baked well. Photo taken with an iphone --ar 4:5 --v 7

Garnishes

A sprinkle of fresh basil or chopped parsley on top after baking can brighten flavors and add a beautiful pop of green. For a bit of texture, toasted pine nuts or a drizzle of good quality olive oil can turn this comforting casserole into something special.

Side Dishes

This hearty casserole pairs wonderfully with a crisp green salad or steamed broccoli to keep the meal balanced. Garlic bread or cheesy breadsticks work nicely too if you want to lean into that pizza vibe.

Creative Ways to Present

Serve the casserole in individual ramekins for a charming presentation, or layer leftovers in clear glass dishes so the colorful layers peek through, tempting everyone to dig in. You can even top with extra toppings like sliced pepperoni or caramelized onions as a fun twist.

Make Ahead and Storage

Storing Leftovers

Leftover Spaghetti Squash Pizza Casserole Recipe keeps well in an airtight container in the refrigerator for up to 3 days. The flavors actually meld beautifully overnight, making the second-day meal even better.

Freezing

This casserole freezes very well—just cover it tightly with foil or plastic wrap and freeze for up to 2 months. When you’re ready to enjoy, thaw overnight in the fridge before reheating for best texture.

Reheating

Reheat individual portions in the microwave or the entire dish in a 350-degree oven until warmed through and bubbly again. Adding a little extra cheese on top before reheating can help revive that fresh-baked feel.

FAQs

Can I use any type of squash for this recipe?

While spaghetti squash is best for its natural noodle-like texture, you can experiment with other firm squashes, but the texture and cooking times may vary.

Do I have to use meat in the casserole?

Not at all! This Spaghetti Squash Pizza Casserole Recipe is incredibly versatile and just as delicious with veggies or even as a cheese-only dish.

How do I cook spaghetti squash quickly?

The Instant Pot is a fantastic tool for speed; you can cook it in about 7 minutes under high pressure, making meal prep super easy.

Can I make this recipe vegan?

Absolutely! Just swap the mozzarella and parmesan for your favorite plant-based cheeses, and choose vegetable-based add-ins to keep things plant-friendly.

Is this casserole suitable for meal prep?

Definitely! It’s perfect for making ahead, storing in portions, and reheating during a busy week while still tasting fresh and comforting.

Final Thoughts

This Spaghetti Squash Pizza Casserole Recipe is such a joy to make and to eat—it hits all the right notes from familiar pizza flavors to nourishing veggies and melty cheese. I really hope you give it a try soon because it’s one of those dishes that feels like a warm hug on a plate. Delicious, easy, and endlessly adaptable, it’s sure to become a favorite in your recipe rotation!