Mar 21, 2025

Spaghetti Squash Lasagna Boats

Prep Time: 10 minutes
Cook Time: 1 hour 30 minutes
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Spaghetti squash is first roasted and the flesh is scraped out and combined with creamed spinach then layered with marinara sauce and topped with mozzarella for that stringy cheese-topped finish
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While spaghetti squash isn’t exactly a pasta dupe, it shines in its own right – especially when paired with cozy, familiar flavors. This spaghetti squash lasagna boat is a delicious, satisfying vegetarian meal that brings all the comfort of classic lasagna, just with a lighter twist.

In this recipe, roasted spaghetti squash is mixed with creamy spinach, then layered with rich marinara and plenty of melty mozzarella for that irresistible cheesy finish. It’s hearty, wholesome, and perfect for when you’re craving something warm and comforting but still want to keep things on the healthier side.

Spaghetti Squash Lasagna Boats

spaghetti squash lasagna boats with fork pulling mixture.

Key Ingredients in This Recipe

  • Spaghetti squash – The reason so many people use it as a pasta substitute is because of the way the flesh becomes stringy, resembling spaghetti noodles (i.e. the name spaghetti squash) sans the fancy spiralizer equipment. I love this type of squash for its mild squash flavor and the way that it can be easily made into boats and loaded with all sorts of ingredients.
  • Mozzarella – I use part-skim, also called low-moisture mozzarella in this recipe. Fresh mozzarella has a higher water content and it becomes runny rather than gooey as it melts. 
  • Spinach – It’s amazing how much spinach you can put into the pan and the minimal ball that comes out. The creamed spinach adds a contrasting rich and creamy element to the homemade marinara sauce in these boats.
  • Tomato sauce – While this recipe calls for homemade marinara sauce,  store-bought sauce can be used as as a substitute. There’s nothing wrong with canned sauce and it can be an easy shortcut, but since the homemade sauce only requires a few ingredients, I typically prefer to make my own.

How to Make Spaghetti Squash Lasagna Boats

scooped out halved spaghetti squash.
Step 1: Prep the squash

Scoop out the seeds and discard. Rub the insides with olive oil.

Step 2: Roast the squash.

Place cut side down on a baking sheet and roast at 400ºF (200ºC) for 45 minutes, until fork-tender. Let cool slightly, then use a fork to scrape the strands into a bowl. Set aside.

roasted spaghetti squash with fork.
homemade marinara sauce with herbs.
Step 3: Make the marinara.

Sauté chopped onion in olive oil until soft (about 6 minutes). Add minced garlic and cook for 1 minute. Stir in crushed tomatoes, dried herbs, and red pepper flakes. Simmer for 20 minutes. Season with salt and pepper.

Step 4: Make the creamed spinach.

Melt butter in a sauté pan, then add garlic and cook briefly. Whisk in flour and cook for 1 minute. Add the milk and stir until thickened (about 2 minutes). Add spinach and cook until wilted (about 4 minutes).

creamed spinach in a sauté pan.
creamed spinach and spaghetti squash in mixing bowl.
Step 5: Combine.

Stir the creamed spinach into the cooked spaghetti squash. Season with salt.

Step 6: Assemble the boats.

Heat oven to 425ºF (220ºC). Spoon marinara into the bottom of each squash half. Fill with the squash-spinach mix. Top with more marinara and mozzarella.

spaghetti squash lasagna boats filled with marinara, spinach and mozzarella.
spaghetti squash lasagna boats topped with arugula salad.
Step 7: Bake and finish.

Bake for 10 minutes, until the cheese is bubbly. Garnish with Parmesan and arugula before serving

Tips and Tricks for This Recipe

  • You can even add seared Italian sausage to the tomato sauce for a more complete entrée (or for someone who just can’t pass up even one night of meat).
  • While I use a homemade tomato sauce in this recipe, a store-bought sauce can be substituted for a shortcut.
spaghetti squash lasagna boat topped with arugula and cheese.

Other Recipes to Try

If you enjoy this spaghetti squash lasagna recipe, I recommend checking out some of these:

Spaghetti Squash Lasagna Boats

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spaghetti squash lasagna boats with mozzarella cheese.
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Prep Time 10 minutes
Cook Time 1 hour 30 minutes
Serves 4

Ingredients:

For the spaghetti squash:

  • 2 medium spaghetti squash, (about 4 pounds total), halved
  • 2 tablespoons extra-virgin olive oil divided

For the marinara sauce:

  • 2 tablespoons extra-virgin olive oil
  • 1 medium yellow onion, diced
  • 2 cloves garlic, chopped
  • 1 (28-ounce) can crushed tomatoes
  • ½ teaspoon dried parsley
  • ½ teaspoon dried oregano
  • ½ teaspoon dried basil
  • ½ teaspoon crushed red pepper
  • Kosher salt, to taste
  • Freshly ground black pepper, to taste

For the creamed spinach:

  • 3 tablespoons unsalted butter
  • 3 cloves garlic, minced
  • 1 tablespoon all-purpose flour
  • ¾ cup whole milk
  • 16 ounces baby spinach
  • Kosher salt, to taste

For assembly:

  • 2 cups shredded mozzarella cheese
  • ½ cup freshly grated Parmesan
  • Handful wild arugula, for garnish

Instructions:

For the spaghetti squash:

  • Scoop out the seeds of the spaghetti squash using a spoon and discard.
  • Preheat oven to 400ºF (200ºC). Rub the inside of each half with the olive oil.  Bake until the spaghetti squash is tender when poked with a fork, about 45 minutes. Let cool for 6 minutes then use a fork to scrape flesh from top to bottom. Remove and set aside in a bowl.

For the marinara sauce:

  • Heat a medium saucepan over medium heat, add the olive oil and heat through. Add the onion and sauté until tender, stirring occasionally, about 6 minutes. Add the garlic and sauté for an additional minute.
  • Stir in the crushed tomatoes, parsley, oregano, basil and red pepper. Turn the heat down to medium-low and simmer the sauce for 20 minutes. Season the sauce to taste with salt and pepper.

For the creamed spinach:

  • Heat a large sauté pan over medium heat, add the butter and allow to melt. Add the garlic and sauté, stirring until fragrant, about 30 seconds.
  • Add the flour, whisking to combine. Let the roux cook until a pale golden brown, about a minute. Add the milk, whisking to combine. Bring to a simmer then lower heat to medium low until thickened, about 2 minutes.
  • Add the spinach, tossing to coat all the leaves in the oil. Sauté the spinach, stirring occasionally, until all the leaves have wilted, about 4 minutes. Remove to a large bowl and return the pan to the heat.
  • Combine the spinach mixture with the spaghetti squash flesh in the bowl, stirring to combine, and evenly coat the squash. Season with salt and set aside.

For assembly:

  • Heat oven to 425ºF (220ºC).
  • Arrange the spaghetti squash boats, cut side up on a baking sheet. Spread ¼ cup of marinara sauce in the bottom of each boat, then fill with the spinach and spaghetti squash mixture. Top each with an additional ¼ cup of the sauce then top with the mozzarella cheese.
  • Bake until the cheese has melted and begins to bubble, about 10 minutes. Remove and let cool then top with Parmesan cheese and arugula to garnish. Serve hot.

Notes:

Add seared Italian sausage to the tomato sauce for a more complete entrée.
While I use a homemade tomato sauce in this recipe, a store-bought sauce can be substituted for a shortcut.

Nutrition:

Calories: 710kcal | Carbohydrates: 48g | Protein: 25g | Fat: 50g | Saturated Fat: 19g | Polyunsaturated Fat: 5g | Monounsaturated Fat: 23g | Trans Fat: 0.3g | Cholesterol: 83mg | Sodium: 767mg | Potassium: 1361mg | Fiber: 11g | Sugar: 18g | Vitamin A: 12117IU | Vitamin C: 45mg | Calcium: 697mg | Iron: 5mg
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