This Spaghetti Squash Casserole is what happens when you take everything you love about a cheesy baked spaghetti dinner and swap the noodles for tender, roasted squash strands.
It bakes up bubbly, saucy, and golden on top, and nobody at my table has ever noticed there’s no pasta involved.
I make this one on repeat during the fall and winter months, when spaghetti squash is cheap and plentiful at the grocery store.
It reheats well, freezes well, and gives you that cozy, cheesy comfort food feeling without the heavy carb load of a traditional baked spaghetti.
If you’ve never cooked with spaghetti squash before, don’t worry. It’s a forgiving vegetable, and once you learn the roasting trick, you’ll want to put it in everything.
| Quick Recipe Summary | |
|---|---|
| Prep Time | 20 minutes |
| Cook Time | 1 hour 5 minutes |
| Total Time | 1 hour 25 minutes |
| Servings | 6 servings |
| Difficulty Level | Easy |
This dish also reminds me a lot of my Butternut Squash Casserole Recipe, just built around a savory Italian flavor profile instead of a sweet one.
Why You’ll Love This Spaghetti Squash Casserole Recipe
This casserole gives you all the comfort of a classic baked spaghetti dinner, but it’s lighter, lower in carbs, and packed with vegetables.
It’s also a fantastic way to use up spaghetti squash if you’ve bought one and aren’t sure what to do with it.
You might also enjoy: Squash Casserole Recipe if you want another cozy way to use squash in the oven.
Here’s why this recipe earns a permanent spot in the dinner rotation:
- Naturally lower in carbs than traditional pasta bakes, since the squash replaces the noodles entirely
- Meal prep friendly, since it holds up beautifully in the fridge for days
- Freezer friendly, so you can make a double batch and stash one for later
- Kid approved, because the cheese and marinara flavors are familiar and comforting
- Easy to customize with different proteins, cheeses, or spice levels
- One dish wonder, since it covers your protein, vegetable, and starch alternative all in one casserole
Ingredients
Everything here is easy to find at a regular grocery store, though I’ve linked a couple of specialty picks that make the dish taste a little more special.
I learned to always splurge on good cheese for this recipe while perfecting my Zucchini and Squash Casserole Recipe, and the same rule applies here.
For the squash:
- 2 medium spaghetti squash (about 3 to 4 pounds each)
- 2 tablespoons olive oil
- Salt and black pepper, to taste
For the meat sauce:
- 1 tablespoon olive oil
- 1 pound ground beef or Italian sausage, casings removed
- 1 small yellow onion, diced
- 3 cloves garlic, minced
- 1 jar (24 ounces) marinara sauce
- 1 teaspoon Italian seasoning
- 1/2 teaspoon crushed red pepper flakes, optional
- 1/2 teaspoon salt
- 1/4 teaspoon black pepper
For the cheese filling:
- 15 ounces ricotta cheese
- 1 large egg
- 1/4 cup grated Parmigiano Reggiano cheese
- 2 tablespoons chopped fresh parsley
For the topping:
- 2 cups shredded mozzarella cheese, divided
- 2 tablespoons chopped fresh basil, for garnish
Kitchen Equipment Needed
Nothing fancy is required for this recipe, though a few good tools make the process much smoother.
Read Also: Baked Cream Cheese Spaghetti Casserole Recipe
- Large rimmed baking sheet, for roasting the squash
- A sharp chef’s knife, for cutting the squash in half
- Large skillet or cast iron skillet, for browning the meat sauce
- A 9×13 ceramic baking dish, for assembling and baking the casserole
- Two forks, for shredding the roasted squash into strands
- Mixing bowls
- Aluminum foil
Recommended Products for This Recipe
These are a few products I personally reach for whenever I make this casserole, based on what has actually made a difference in my own kitchen.
1. Le Creuset Enameled Cast Iron Baking Dish
I have used this baking dish for years, and it holds heat so evenly that the top of the casserole browns beautifully without scorching the edges.
The enameled surface also makes cleanup simple, even with baked on cheese. It is an investment piece, but it will outlast several cheaper baking dishes.
2. Parmigiano Reggiano Wedge
Pre-shredded parmesan from a bag is fine in a pinch, but grating a real wedge of Parmigiano Reggiano yourself changes the flavor of this whole dish.
It melts smoother and tastes noticeably nuttier than the shelf stable stuff.
3. Instant Read Meat Thermometer
This takes the guesswork out of knowing when your ground beef or sausage is fully cooked. I use mine for almost every savory recipe I make, not just this one.
4. Wusthof Chef’s Knife
Cutting a raw spaghetti squash in half is the trickiest part of this whole recipe, and a sharp, well balanced knife makes it far less intimidating. This one has held its edge for me for years.
Another favorite: Summer Squash Puffs Recipe
Step-by-Step Instructions: How to Make Spaghetti Squash Casserole
1. Roast the Spaghetti Squash
- Preheat your oven to 400 degrees Fahrenheit.
- Carefully cut each spaghetti squash in half lengthwise using a sharp chef’s knife. If the squash is hard to cut, microwave it whole for 3 to 4 minutes first to soften the skin slightly.
- Use a spoon to scoop out and discard the seeds and stringy pulp from the center of each half.
- Drizzle the cut sides with olive oil and season with salt and pepper.
- Place the squash halves cut side down on a large rimmed baking sheet lined with foil.
- Roast for 40 to 45 minutes, or until the flesh is tender and easily pierced with a fork.
- Remove from the oven and let the squash cool for 10 minutes before handling. Keep the oven on, but lower the temperature to 375 degrees Fahrenheit for the casserole bake.
2. Shred the Squash Strands
- Once the squash halves are cool enough to handle, hold each half steady and use a fork to scrape the flesh lengthwise from the skin.
- The strands will naturally separate into spaghetti like ribbons.
- Transfer the shredded squash to a large mixing bowl.
- Press the squash gently with paper towels or a clean kitchen towel to remove excess moisture. This step keeps the finished casserole from turning watery.
3. Cook the Meat Sauce Base
- While the squash roasts, heat 1 tablespoon of olive oil in a large skillet over medium heat.
- Add the diced onion and cook for 3 to 4 minutes, until softened and translucent.
- Add the minced garlic and cook for another 30 seconds, stirring constantly so it doesn’t burn.
- Add the ground beef or Italian sausage to the skillet, breaking it apart with a wooden spoon.
- Cook for 6 to 8 minutes, until the meat is fully browned and no pink remains. Drain any excess grease.
- Stir in the marinara sauce, Italian seasoning, crushed red pepper flakes, salt, and black pepper.
- Simmer the sauce for 5 minutes, stirring occasionally, then remove from the heat.
4. Mix the Ricotta Filling
- In a separate mixing bowl, combine the ricotta cheese, egg, grated Parmigiano Reggiano, and chopped parsley.
- Stir until the mixture is smooth and evenly combined.
- Set this bowl aside while you assemble the casserole.
5. Assemble the Casserole
- Lightly grease your 9×13 ceramic baking dish with olive oil or cooking spray.
- Spread half of the shredded spaghetti squash evenly across the bottom of the dish.
- Dollop and gently spread the ricotta mixture over the layer of squash.
- Spoon half of the meat sauce over the ricotta layer.
- Add the remaining shredded squash on top, followed by the rest of the meat sauce.
- Sprinkle 1 cup of the shredded mozzarella evenly over the top, reserving the second cup for later.
6. Bake to Bubbly Perfection
- Cover the baking dish loosely with foil.
- Bake at 375 degrees Fahrenheit for 20 minutes.
- Remove the foil, sprinkle the remaining 1 cup of mozzarella over the top, and return the dish to the oven uncovered.
- Bake for another 10 to 15 minutes, until the cheese is melted, golden, and bubbling around the edges.
7. Rest, Garnish, and Serve
- Remove the casserole from the oven and let it rest for 10 minutes before slicing. This resting time helps the layers set so your slices hold together.
- Sprinkle the fresh basil over the top just before serving.
- Slice into six portions and serve warm.
This same roasting method is the foundation of my Baked Acorn Squash Recipe, if you want to practice on a smaller squash first.
Tips for The Best Spaghetti Squash Casserole
A few small details make the difference between a watery casserole and one with clean, sliceable layers.
Another favorite of mine for the same reason: Baked Chicken Spaghetti Recipe.
- Always drain the roasted squash well before assembling, since it holds a surprising amount of water
- Choose spaghetti squash that feels heavy for its size and has smooth, unblemished skin
- Roast the squash cut side down for the best texture and to prevent it from drying out
- Let the casserole rest for a full 10 minutes before cutting so the layers stay intact
- Use freshly grated cheese rather than pre-shredded bags, since it melts more smoothly
- Taste your meat sauce before assembling and adjust the seasoning as needed
Serving Suggestions
This casserole is hearty enough to serve on its own, but I almost always round it out with something bright and green on the side.
A simple salad or roasted vegetable cuts through the richness of the cheese and sauce nicely.
- A crisp cucumber salad for a cool, tangy contrast
- Warm garlic bread for scooping up extra sauce
- Steamed green beans or roasted broccoli
- A simple side salad with vinaigrette
- Sauteed spinach with garlic
- Roasted Chicken and Summer Squash if you want to double down on squash
Variations of Spaghetti Squash Casserole
This recipe is easy to adapt depending on what you have on hand or what your family prefers.
Read Also: Baked Alfredo Spaghetti Recipe
- Vegetarian version: Skip the meat entirely and add sauteed mushrooms, spinach, or zucchini instead
- Spicy version: Increase the crushed red pepper flakes or stir in a spoonful of chili crisp
- White sauce version: Swap the marinara and meat sauce for an alfredo sauce and rotisserie chicken
- Extra veggie version: Fold in chopped bell peppers, mushrooms, or baby spinach with the meat sauce
- Different protein: Try ground turkey, ground chicken, or plant based crumbles in place of beef
- Extra cheesy version: Add a layer of provolone or fontina along with the mozzarella
Storage and Reheating
This casserole is one of those recipes that tastes just as good, if not better, the next day.
This same make ahead friendly approach works well for my Vegetarian Baked Spaghetti Recipe too.
- Store leftovers in an airtight container in the refrigerator for up to 4 days
- Reheat individual portions in the microwave for 1 to 2 minutes, until warmed through
- Reheat larger portions in a 350 degree Fahrenheit oven, covered with foil, for about 20 minutes
- To freeze, cool the casserole completely and wrap tightly in foil and plastic wrap, or transfer to a freezer safe container
- Frozen casserole keeps well for up to 3 months
- Thaw overnight in the refrigerator before reheating in the oven
Nutritional Facts
This casserole is naturally lower in carbohydrates than a traditional pasta bake, since spaghetti squash takes the place of noodles.
Read Also: Southern Baked Spaghetti Recipe
A typical serving of this casserole, based on 6 servings per recipe, includes approximately:
- Calories: 420 per serving
- Protein: 26 grams
- Carbohydrates: 18 grams
- Fat: 27 grams
- Fiber: 4 grams
- Sodium: 680 milligrams
These figures will vary depending on the exact brands of marinara sauce, cheese, and meat you use.
Health Benefits of Key Ingredients
Beyond tasting great, this casserole brings a few genuinely useful nutrients to the table.
Spaghetti squash in particular is a smart swap if you are trying to eat a few more vegetables without giving up comfort food.
- Spaghetti squash is naturally low in calories and a good source of vitamin C and fiber
- Ricotta cheese provides calcium and protein to help keep the dish satisfying
- Ground beef delivers iron, zinc, and vitamin B12
- Garlic and onion contain antioxidants that support immune health
- Tomatoes in marinara sauce are a good source of lycopene, an antioxidant linked to heart health
- Parmigiano Reggiano adds calcium along with a concentrated, savory flavor in a small amount
You might also enjoy: Chicken and Rice Casserole Recipe for another protein packed comfort dish.
FAQs About Spaghetti Squash Casserole
1. Can I make this casserole ahead of time?
Yes, you can assemble the full casserole up to a day in advance and store it covered in the refrigerator.
Add about 10 extra minutes to the covered baking time if you are starting from cold.
2. Why is my spaghetti squash watery?
Spaghetti squash naturally holds a lot of moisture, especially if it was roasted at a lower temperature or not drained well.
Pressing the shredded strands with a towel before assembling the casserole solves this problem.
3. Can I use a different sauce instead of marinara?
Absolutely, an alfredo or vodka sauce both work beautifully in place of marinara.
Just keep the sauce quantity roughly the same so the layers stay balanced.
4. How do I know when the spaghetti squash is done roasting?
The squash is ready when a fork easily pierces the flesh and it separates into strands without resistance.
If it still feels firm, return it to the oven in 5 minute increments until tender.
5. Can I make this recipe without meat?
Yes, this recipe works well as a vegetarian dish.
Simply omit the ground beef and add extra vegetables like mushrooms, spinach, or bell peppers to the sauce for texture.
Read Also: Million Dollar Baked Spaghetti Recipe
Spaghetti Squash Casserole
Ingredients
- 2 spaghetti squash about 3 to 4 pounds each
- 2 tablespoons olive oil for squash
- Salt and black pepper to taste
- 1 tablespoon olive oil for meat sauce
- 1 pound ground beef or Italian sausage 454g, casings removed if using sausage
- 1 small yellow onion diced, about 1 cup or 150g
- 3 cloves garlic minced
- 1 jar marinara sauce 24 ounces or 680g
- 1 teaspoon Italian seasoning
- 1/2 teaspoon crushed red pepper flakes optional
- 1/2 teaspoon salt
- 1/4 teaspoon black pepper
- 15 ounces ricotta cheese 425g
- 1 large egg
- 1/4 cup Parmigiano Reggiano cheese grated, about 25g
- 2 tablespoons fresh parsley chopped
- 2 cups shredded mozzarella cheese divided, about 8 ounces or 225g total
- 2 tablespoons fresh basil chopped, for garnish
Equipment
- Large rimmed baking sheet For roasting squash
- Sharp chef’s knife For cutting the squash in half
- Large skillet or cast iron skillet For browning the meat sauce
- 9×13 ceramic baking dish For assembling and baking
- Two forks For shredding the roasted squash
- Mixing bowls
- Aluminum foil
Method
- Preheat oven to 400°F. Cut each spaghetti squash in half lengthwise, scoop out seeds and pulp, drizzle with olive oil, and season with salt and pepper. Place cut side down on a foil-lined baking sheet and roast for 40-45 minutes until tender.
- Let squash cool for 10 minutes, then use forks to scrape flesh into spaghetti-like strands. Transfer to a bowl and press gently with paper towels to remove excess moisture. Reduce oven temperature to 375°F.
- Heat 1 tablespoon olive oil in a large skillet over medium heat. Cook onion for 3-4 minutes until softened, add garlic for 30 seconds, then brown the ground meat for 6-8 minutes. Drain excess grease, stir in marinara, Italian seasoning, red pepper flakes, salt, and pepper, and simmer for 5 minutes.
- In a mixing bowl, combine ricotta, egg, Parmigiano Reggiano, and parsley until smooth.
- Grease a 9×13 baking dish. Layer half the squash, all the ricotta mixture, half the meat sauce, remaining squash, and remaining meat sauce. Top with 1 cup mozzarella.
- Cover with foil and bake at 375°F for 20 minutes. Uncover, sprinkle with remaining 1 cup mozzarella, and bake for another 10-15 minutes until bubbly and golden.
- Rest for 10 minutes before slicing. Garnish with fresh basil and serve warm.
Nutrition
Notes
- Always drain the roasted squash well before assembling to prevent a watery casserole. Pressing with paper towels or a clean kitchen towel makes a big difference.
- Choose spaghetti squash that feels heavy for its size with smooth, unblemished skin for the best texture and flavor.
- Roast the squash cut side down for the best texture and to prevent it from drying out during roasting.
- Let the casserole rest for a full 10 minutes before cutting so the layers stay intact when served.
- For the best melting and flavor, use freshly grated cheese rather than pre-shredded bags which contain anti-caking agents.
- To make ahead: assemble the full casserole up to a day in advance and store covered in the refrigerator. Add 10 extra minutes to covered baking time if starting cold.
- Freezer instructions: Cool completely, wrap tightly in foil and plastic wrap, and freeze for up to 3 months. Thaw overnight in the refrigerator before reheating.
- Vegetarian version: Omit the meat and add sautéed mushrooms, spinach, or zucchini to the sauce for a hearty meatless meal.
- White sauce version: Swap the marinara and meat sauce for alfredo sauce and add rotisserie chicken for a creamy twist.
- Individual portions reheat beautifully in the microwave for 1-2 minutes for quick leftovers.
Private Notes
Tried this recipe?
Let us know how it was!Conclusion
This Spaghetti Squash Casserole has become one of those recipes I make without even thinking twice about it anymore.
It is cozy, cheesy, and a genuinely satisfying way to get more vegetables into a weeknight dinner.
Give it a try this week, and let me know in the comments how your family liked it.
If you make any tweaks of your own, I would love to hear about them too.
Recommended:
- Baked Spaghetti with Ricotta Cheese
- Chicken and Wild Rice Casserole Recipe
- Fazoli’s Baked Spaghetti Recipe
- Pasta Primavera Recipe
- Zucchini Noodles with Pesto
