This easy spaghetti squash lasagna is a deliciously cheesy dinner! Made with just a few simple ingredients, this low-carb, vegetarian lasagna is a tasty main dish!

spaghetti squash lasagna
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On Tuesday night, when Alex gave this meal two thumbs up, I explained that it was actually pretty healthy and he responded: “If this is healthy, we should eat it every night.” So there you go folks, this one was a winner. The reason it doesn’t taste healthy is because the cheese is the star of the show here. The squash helps bulk up the serving size so you feel like you’re eating a big bowl of cheesy goodness when it’s really full of vegetables. See what I did there?

I’ll warn you that this lasagna won’t come out in beautiful stacked layers. It’s definitely a little messier since you’re using small strands of squash and not big noodles. I’d recommend serving this in a bowl and not on a plate.

spaghetti squash

How to Cook Spaghetti Squash

There are a few ways to cook the spaghetti squash for this recipe. I recommend the microwave because it’s the fastest option, but you can also cook it in the oven.

Microwave method: Carefully slice your spaghetti squash in half. Scoop out the seeds and flip the halves cut side down on a large microwave-safe plate. Add a little water to the bottom of the plate (to create steam) and microwave on high for 10 minutes. Remove from the microwave, let cool slightly, then use a fork to scrape out the strands. For this recipe, you don’t want to overcook the squash since you’ll be putting it in the oven.

Oven method: Carefully slice your spaghetti squash in half. Scoop out the seeds and flip the halves cut side down on a large baking sheet. Bake at 400 degrees for 20-25 minutes until softened. Let cool slightly, then use a fork to scrape out the strands. For this recipe, you don’t want to overcook the squash since you’ll be putting it back in the oven. I recommend only baking for 20 minutes, then scrape out the strands.

Instant Pot method: You can actually cook spaghetti squash in an Instant Pot which is quick and easy! Check out the blog post for the full instructions.

Spaghetti Squash Lasagna Ingredients

  • Spaghetti squash– This type of squash is a large, yellow oval-shaped squash. It’s a unique type of squash that has noodle-type strands. Do not try to substitute a different kind of squash.
  • Marinara sauce– Be sure to use a thick, chunky sauce. Avoid a watery sauce, which will make the final dish soggy. I also recommend a sauce without any added sugar.
  • Ricotta cheese– This gives it that creamy, lasagna taste! I recommend using part-skim or whole milk ricotta.
  • Mozzarella– You can use shredded or fresh mozzarella cheese.
  • Fresh basil– This is optional but a sprinkle of fresh basil adds a lovely pop of color!

Substitution Ideas

I haven’t tried making this recipe vegan, but if you do want to give it a try, I recommend using Kite Hill’s vegan ricotta and Violife’s mozzarella. If you’re local to Richmond, check out Unmoo for a great vegan mozzarella. It’s the best vegan cheese I’ve found, but it’s only sold locally.

What Does Spaghetti Squash Taste Like?

Spaghetti squash has a subtle sweetness, but it has a pretty mild flavor, making it a great pasta substitute. After it’s cooked, you can use a fork to separate the noodle-like strands of the squash. Cook the squash until it’s tender, but not mushy.

Tips for Perfect Spaghetti Squash Lasagna

  • Microwaving the squash significantly reduces the time to make this recipe, but if you want to roast the squash in the oven, you can. You’ll need to roast it for 20-30 minutes, and then continue on with the rest of the steps.
  • The nutritional information is based on part-skim cheeses. Do NOT use fat-free cheese or it won’t taste nearly as good. You can use full-fat cheese if you like, but the nutritional stats will be a bit higher.
  • Let the lasagna sit for a few minutes after it comes out of the oven. This will help it set and make it easier to serve.
pasta sauce

The Best Pasta Sauce for Spaghetti Squash Lasagna

Use a thick pasta sauce. Since the squash contains moisture, using a thicker marinara sauce will help prevent the lasagna from being watery. I really like Rao’s tomato basil pasta sauce which has a great flavor and no added sugar. Avoid a sauce with added sugar, as spaghetti squash already has a subtle sweetness and any added sugar could make the final dish too sweet.

How to Keep Spaghetti Squash from Being Mushy

To reduce the water content of the squash, gently press the cooked squash strands in a mesh strainer. It won’t get rid of all the moisture, but it will help. Also, using a thick, chunky marinara sauce will help prevent the finished dish from being watery.

Is Spaghetti Squash Healthy?

Yes! Spaghetti squash is great for a diet, whether you’re trying to eat low carb, vegetarian, or you just want to add more vegetables to your plate. It’s packed with nutrients like folic acid, potassium, and beta carotene. Plus, it’s very low in calories! With less than 50 calories per cup, it’s a great “high volume” food!

How to Make Spaghetti Squash Lasagna

Once your spaghetti squash is cooked, drain the noodles by pressing gently into a mesh strainer.

spaghetti squash noodles

Start with a little sauce in the bottom of the pan.

sauce in the bottom of the pan

Add a layer of spaghetti squash noodles on top of the sauce.

spaghetti squash lasagna

Top that with the sauce and ricotta mixture, then repeat with a layer of squash and a layer of sauce.

spaghetti squash lasagna

Add a layer of mozzarella on top, then cover with foil before baking.

spaghetti squash lasagna

Remove the foil for the last two minutes of baking, and broil until the cheese is bubbly and browned.

spaghetti squash lasagna

Let stand for a few minutes, then serve!

What to Serve with Spaghetti Squash Lasagna

If you’re looking for the perfect side dish to pair with this lasagna, try one of these side dishes to serve with pasta! Even though this lasagna isn’t made with pasta, it has all the same flavors of your favorite lasagna ! You could also pair this dish with this Warm Kale Salad or my favorite Italian Chopped Salad.

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spaghetti squash lasagna

Spaghetti Squash Lasagna

5 Stars 4 Stars 3 Stars 2 Stars 1 Star 4.9 from 32 reviews
  • Author: Liz Thomson
  • Prep Time: 15 mins
  • Cook Time: 40 mins
  • Total Time: 55 minutes
  • Yield: 4 servings 1x
  • Category: Dinner
  • Method: Baking
  • Cuisine: Italian

Description

This easy spaghetti squash lasagna is a deliciously cheesy dinner! Made with just a few simple ingredients, this low carb vegetarian lasagna is a tasty main dish!


Ingredients

Scale
  • 1 medium spaghetti squash (about 3 cups cooked)
  • 2 cups of marinara sauce
  • 1/2 cup part skim ricotta cheese
  • 1 1/2 cups part skim shredded mozzarella
  • Handful of fresh basil or parsley for garnish

Instructions

  1. Preheat the oven to 400 degrees.
  2. Carefully slice your spaghetti squash in half. (Be careful!)
  3. Use a spoon to scoop out the seeds and flip them cut side down on a large microwave-safe plate.
  4. Add a little water to the bottom of the plate (to create steam) and microwave on high for 10 minutes.
  5. In a small casserole dish (6×8 or 8×8) add a thin layer of tomato sauce to the bottom.
  6. Combine the rest of the tomato sauce with the ricotta cheese.
  7. Once the spaghetti squash is done in the microwave, let it cool, then scoop out the insides with a fork.
  8. Layer the spaghetti squash over the sauce.
  9. Top with sauce and repeat with spaghetti squash.
  10. Cover the whole pan with mozzarella cheese and cover with aluminum foil.
  11. Bake at 400 for about 20 minutes.
  12. Turn to broil for an additional 2-3 minutes, or until the top becomes brown and bubbly.
  13. Roughly chop the fresh basil and sprinkle over top!

Notes

  • Microwave the squash ahead of time significantly reduces the time to make this, but if you want to roast the squash in the oven, that’s fine. You’ll probably need to roast it for 20-30 minutes, and then continue on with the rest of the steps.
  • To reduce the watery-ness of the squash, you can gently press it in a mesh strainer after removing from the squash shell. It won’t get rid of all the moisture, but it can help.

Believe it or not, 1/4 of this whole pan is less than 250 calories and has 16g of protein! This is a great low-carb dinner recipe if you’re craving something cheesy but you still want to eat healthy!

More Spaghetti Squash Recipes

Looking for more spaghetti squash ideas? Try this Spaghetti Squash Gratin or make this spaghetti squash Pomodoro.

spaghetti squash with sauce

What’s your favorite way to eat spaghetti squash?