Spaghetti Squash Casserole
Spaghetti squash casserole is the low-carb dinner that fills you up and keeps the whole table happy. The squash roasts into tender strands that hold all that cheesy, saucy goodness together just like pasta would. Ricotta, mozzarella, and a rich marinara sauce make this baked spaghetti squash casserole worth repeating.
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Why This Spaghetti Squash Casserole Recipe Works
Most baked spaghetti squash casserole recipes stop at marinara and shredded mozzarella. Adding ricotta is what makes this taste like a creamy lasagna instead of a basic veggie bake.
Roasting the squash cut-side down is the move that makes everything work. It locks in moisture and gives you strands that are tender without getting watery. I’ve tested both methods, and this way gives you a far better texture in the final bake.
If you love a good casserole night, you’ll want to check out this Cheesy Brussels Sprouts Casserole, this Crock Pot Broccoli Casserole, and this Simple Butternut Squash Casserole too.
How To Make Spaghetti Squash Casserole
- Preheat the oven to 400°F. Cut the spaghetti squash in half lengthwise and scoop out the seeds. Drizzle the cut sides with olive oil, then season with salt, black pepper, and garlic powder. Place the halves cut-side down on a parchment-lined baking sheet.
- Roast the squash for 35 to 45 minutes, or until it is tender and the flesh pulls into strands easily with a fork. Let it cool slightly, then scrape out the strands. Press away any excess moisture with a paper towel.
- Heat a little olive oil in a skillet over medium heat. Sauté the diced onion until soft, then add the garlic and cook for 1 minute. Stir in the marinara sauce, Italian seasoning, and any remaining salt and pepper, then simmer for a few minutes.
- Add the spaghetti squash strands to a large bowl with the marinara mixture, ricotta, half of the mozzarella, Parmesan, and the egg, if using. Stir in the cooked ground beef or turkey, if desired, and mix until everything is evenly combined.
- Grease a 9×13-inch baking dish. Spread the spaghetti squash mixture evenly in the prepared dish, smoothing the top into an even layer.
- Sprinkle the remaining mozzarella and a little extra Parmesan over the casserole. Bake at 375°F for 20 to 25 minutes, until hot and bubbly. Broil for 2 to 3 minutes for a golden top, if desired, then let the casserole rest for 10 minutes before serving.
Ingredients
- Spaghetti squash – The star of the dish, roasted until the flesh shreds into noodle-like strands that form the base of the casserole.
- Olive oil – Used to coat the squash before roasting and to saute the aromatics in the skillet.
- Salt and black pepper – Essential seasoning that builds flavor at every layer of this recipe.
- Garlic powder – Adds warm, savory depth to the roasted squash before it even hits the skillet.
- Italian seasoning – Brings that classic herb blend to the sauce without needing to measure out five separate spices.
- Onion – Diced and sauteed until soft, it adds a subtle sweetness to the marinara mixture.
- Garlic – Fresh minced garlic gives the sauce a bold, aromatic base that dried garlic can’t quite replicate.
- Marinara sauce – The saucy backbone of the casserole that pulls all the components together.
- Mozzarella cheese – Shredded and layered inside the filling and on top for that classic bubbly, golden cheese layer.
- Parmesan cheese – Adds a salty, nutty finish that balances the richness of the ricotta and mozzarella.
- Ricotta cheese – The creamy ingredient that sets this recipe apart and makes every bite taste like a layered lasagna.
- Egg (optional) – Helps bind the filling so it holds together cleanly when scooped and served.
- Ground beef or turkey (optional) – Stir in cooked meat to turn this into a full, protein-packed dinner.
Tips for Baked Spaghetti Squash Casserole
- Shred your own mozzarella. Pre-shredded cheese is coated with starches that prevent it from melting smoothly. A block of mozzarella shredded at home makes a big difference in the final texture.
- Press the squash strands before mixing. After scraping, press out any excess moisture with a paper towel. Too much water in the casserole makes the filling soggy.
- Taste your marinara before adding it. Taste it first, and season with extra Italian seasoning or red pepper flakes if it needs a boost.
- Add the optional egg. It really does help the filling set and makes serving much cleaner. It doesn’t change the flavor at all.
- Use a 9×13 dish, not smaller. The filling needs room to spread in an even layer so everything cooks consistently.
- Broil for 2 to 3 minutes at the end. If you want a golden, slightly crisp cheese topping, switch on the broiler for the last few minutes. Keep a close eye on it.
Common Mistakes to Avoid When Making Baked Spaghetti Squash Casserole
- Adding squash before it cools. Hot strands will melt the ricotta and cheese before the casserole even hits the oven. Let it cool at least 10 minutes before mixing.
- Using too much marinara. More sauce sounds good, but it adds excess liquid that pools in the bottom of the casserole. Stick to 2 cups for the right consistency.
- Skipping the resting time. Cutting into this straight from the oven means everything runs and falls apart. Ten minutes of rest time makes it hold together perfectly.
- Roasting cut-side up. This traps steam and leaves you with watery, harder-to-scrape strands that taste blander in the final casserole.
- Forgetting to grease the baking dish. The cheese layer on the bottom will stick and tear when you serve it. A quick spray saves the whole presentation.
FAQs
Yes. Assemble the casserole up to 24 hours ahead and keep it covered in the refrigerator. Bake it when you’re ready, adding 5 to 10 extra minutes since it’s starting cold.
The outside will look golden and the skin will feel soft when you press it. When you flip it over, the flesh should shred easily into strands with a fork.
Absolutely. Brown the ground beef and drain it well before adding it to the filling. It makes the casserole heartier and adds a meaty, savory depth that the whole family tends to love.
Yes. Spaghetti squash has significantly fewer carbs than pasta, and this recipe uses no bread, flour, or starchy fillers. It’s a solid option if you’re watching carbs but still want a filling dinner.
How to Store and Reheat
- Storage: Leftover spaghetti squash casserole keeps well in an airtight container in the refrigerator for up to 4 days. Let it cool completely before sealing to prevent condensation from making it watery.
- Freezing: This casserole can be frozen, though the squash strands may release some water when thawed. Freeze individual portions in airtight containers for up to 2 months, and thaw overnight in the refrigerator before reheating.
- Reheating: Reheat individual servings in the microwave in 60-second intervals until warmed through. For the full casserole, cover with foil and warm in a 350°F oven for 20 to 25 minutes, then remove the foil for the last 5 minutes to re-melt the cheese topping.
More Easy Dinner Casseroles
Looking for more easy casserole dinners the family will love?
Try this Hashbrown Hamburger Casserole, Zuppa Toscana Casserole, Chicken Hashbrown Casserole, Broccoli Chicken Potato Casserole, or Chicken Spinach and Artichoke Casserole.
Spaghetti Squash Casserole
Equipment
- 1 9×13 inch baking dish for baking the casserole
- Large bowl
Ingredients
- 1 large spaghetti squash
- 2 tablespoons olive oil
- 1 teaspoon salt
- ½ teaspoon black pepper
- 1 teaspoon garlic powder
- 1 teaspoon Italian seasoning
- 1 small onion diced
- 3 cloves garlic minced
- 2 cups marinara sauce
- 1 ½ cups shredded mozzarella cheese
- ½ cup grated Parmesan cheese
- 1 cup ricotta cheese
- 1 large egg optional, helps bind
- 1 cup cooked ground beef or turkey optional
Instructions
- Preheat the oven to 400°F. Slice the spaghetti squash in half lengthwise and scoop out the seeds. Drizzle with olive oil and sprinkle with salt, black pepper, and garlic powder. Place cut-side down on a baking sheet and roast for 35-45 minutes, until tender. Let cool slightly, then scrape the flesh into strands with a fork.
- In a skillet, sauté the onion in a little olive oil until soft. Add the garlic and cook for 1 minute more. Stir in the marinara sauce, Italian seasoning, and any remaining salt and black pepper. Simmer for a few minutes.
- In a large bowl, combine the spaghetti squash strands with the marinara mixture. Stir in the ricotta, half of the mozzarella, Parmesan, and egg, if using. Add the cooked meat, if desired.
- Spread the mixture into a greased 9×13-inch baking dish. Top with the remaining mozzarella and a sprinkle of Parmesan. Bake at 375°F for 20-25 minutes, until bubbly and golden on top. Let rest for 10 minutes before serving.
Disclaimer:
Any nutritional data I provide is an approximation and actual dietary information can vary based on ingredients and proportion sizes.