This Spaghetti Squash Lasagna is everything you want in lasagna without all the carbs! Tender roasted spaghetti squash is layered with a creamy ricotta filling, rich, flavorful Italian sausage marinara and mozzarella cheese. It’s cheesy, satisfying and can be assembled completely in advance!

Spaghetti squash lasagna on a sheet pan

One of my family’s favorite recipes is my skillet lasagna. Who can argue? It’s cheesy, comforting and you really can’t beat the classics.

That said, last year I took a lighter approach with my zucchini lasagna and my taste testers all agreed that they really didn’t miss the pasta.

This Spaghetti Squash Lasagna is my fall and winter spin on that recipe, and it’s even easier because I don’t even need to dirty up a baking dish.

The spaghetti squash is roasted until tender, shredded, then stuffed with a creamy ricotta filling and marinara sauce with Italian sausage.

It’s topped with grated mozzarella cheese and baked to melted, cheesy perfection.

It’s hands down my favorite way to enjoy lasagna! 🙂

Spaghetti squash lasagna on a sheet pan garnished with basil

Why you’ll love this recipe:

  • Comforting and delicious. These spaghetti squash lasagna boats give you all the cheesy, comforting feels as classic lasagna and delivers big on flavor.
  • It’s a healthier alternative. Spaghetti squash is lower in calories and carbs than pasta, and it’s packed with nutrients like fiber, potassium and Vitamins A, C and K.
  • Great for meal prep. The squash can be prepped 1-2 days in advance, or you can assemble the lasagna boats a day in advance and bake them off when you’re ready.
  • Customizable. The Italian sausage can be subbed out with turkey sausage or your favorite ground meat, or forgo the meat and use chopped fresh mushrooms.

Recipe ingredients

This spaghetti squash lasagna recipe has a few ingredients that are very easy to customize based on your preferences or what you have on hand.

Spaghetti squash lasagna ingredients

Ingredient notes

  • Spaghetti squash. You’ll need (2) spaghetti squash for this recipe. Be sure that they’re on the smaller side, or about 1 1/2 – 2 lbs. each. They can be prepped and cooked completely in advance. You can roast spaghetti squash as per the instructions in the recipe card, or see my post how to cook spaghetti squash for more options.
  • Italian sausage. The Italian sausage adds a ton of flavor, but you can certainly choose turkey sausage for a leaner option. Your favorite ground meat will also work, or use a pound of chopped fresh mushrooms for a vegetarian option.
  • Onions and garlic. The onions and garlic add delicious depth of flavor to the marinara sauce.
  • Marinara sauce. Use my homemade marinara sauce, which you can prep completely in advance, or use your favorite store bought brand.
  • Ricotta cheese. I adore the ricotta filling in my ricotta stuffed shells recipe, so I wanted to add that element here. The ricotta is mixed with the spaghetti squash strands and it takes this recipe over the top.
  • Parmesan cheese. Adds savory flavor to the ricotta mixture.
  • Egg. Ricotta cheese can get watery, so the egg provides structure.
  • Fresh basil. Adds fresh flavor and a pop of color to the filling. I highly recommend garnishing your lasagna boats with additional chopped basil. In a pinch, add 1 teaspoon dried basil.
  • Mozzarella cheese. For the best meltability, grate the cheese yourself.

How to make lasagna with spaghetti squash

Who knew making lasagna with spaghetti squash would be so delicious? The squash pairs beautifully with the layers of ricotta filling and marinara with sausage, and it’s so easy to make.

I’m breaking up the instructions in components below, which outline how to cut spaghetti squash, roasting spaghetti squash, and assembling the boats.

Pro tip: Prep and cook the spaghetti squash 1-2 days in advance to make this meal go even more quickly! You can also assemble the lasagna boats a day ahead and bake them when you’re ready.

See the recipe card below for full instructions.

How to cut a spaghetti squash

How to cut a spaghetti squash
  1. Lay the spaghetti squash horizontally on a cutting board and using a sharp knife, remove the stem.
  2. Stand the spaghetti squash upright on the cut side and using a sharp paring knife, cut the squash in half from the top down one side at a time. You can also use a large knife and cut in half from the middle using a rocking motion, but I don’t advise this if your squash is on the taller, large side.
  3. Turn the squash horizontally once more to cut through the stem to separate it if necessary.
  4. Scoop out the seeds and stringy insides with a large spoon.

Roast spaghetti squash

Roast spaghetti squash
  1. Brush the insides of the squash with a tablespoon of olive oil and season with salt and pepper to taste.
  2. Place cut side down on the baking sheet.
  3. Bake at 400 degrees for 40-45 minutes or until tender.
  4. When cool enough to handle, “shred” the spaghetti squash with a fork.

Assemble and bake

how to make spaghetti squash lasagna
  1. Cook the sausage in a large pan for 5 minutes or until cooked though. Remove from heat and drain all but 1 tablespoon of grease. Add the onion and sauté until softened, then add garlic and cook 30 seconds longer. Add sausage back to the pan along with the marinara sauce and cook 5-8 minutes longer.
  2. Combine the ricotta and egg in a medium bowl. Add the parmesan and basil and stir to combine.
  3. Add the spaghetti squash to the ricotta mixture and stir until incorporated.
  4. Divide the ricotta mixture between the (4) spaghetti squash halves.
  5. Divide the marinara mixture between the (4) spaghetti squash halves.
  6. Top with grated mozzarella and bake at 400 degrees for 10-15 minutes.
Spaghetti squash lasagna boats on a baking sheet

FAQs

Is spaghetti squash lower in carbs than pasta?

Spaghetti squash is significantly lower in carbs than pasta. 1 cup of cooked spaghetti squash contains 10 grams of carbohydrates, while 1 cup of cooked spaghetti contains 47 grams of carbs.

Is spaghetti squash nutritious?

Yes! Spaghetti squash is packed with nutrients like fiber, potassium, and Vitamins A, C and K.

What does spaghetti squash taste like?

The flavor of spaghetti squash is very mild with a slightly sweet, earthy undertone. It’s mild flavor makes it extremely versatile.

Can I make this spaghetti squash lasagna with cottage cheese?

The ricotta cheese can be substituted with cottage cheese for added protein.

Spaghetti squash lasagna boat on a plate with a fork

Serving suggestions

This lasagna with spaghetti squash is pure comfort food, and it can be served up exactly like you would traditional lasagna.

Recipe notes

  • Pro tip:  Prep and cook the spaghetti squash 1-2 days in advance to make this meal go even more quickly! You can also assemble the lasagna boats a day ahead and bake them when you’re ready.
  • Sub the Italian sausage for turkey sausage or your favorite ground meat.  You can also forgo the meat and use 16 ounces of chopped mushrooms.
  • Store spaghetti squash lasagna boats in the refrigerator for up to 3 days.
Fork pulling strands of spaghetti squash lasagna

More Italian recipes you’ll love

Did you try this recipe?  If so, be sure to leave a review below and tag me @flavorthemoments on Facebook and Instagram

Spaghetti squash lasagna on a sheet pan.

Spaghetti Squash Lasagna

Spaghetti Squash Lasagna is everything you want in lasagna without all the carbs! Tender roasted spaghetti squash is tossed with a creamy ricotta filling, then topped with a rich, flavorful Italian sausage marinara and mozzarella cheese. It's cheesy, satisfying and can be assembled completely in advance!
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Ingredients

  • 2 spaghetti squash on the smaller side, about 1 1/2 – 2 lbs. each
  • 2 tablespoons olive oil divided
  • 16 ounces Italian sausage casings removed
  • 1 onion chopped
  • 3 cloves garlic minced
  • 2 cups marinara sauce homemade or store bought
  • 1 cup ricotta cheese use more ricotta as necessary to coat the spaghetti squash; sub with cottage cheese
  • 1 large egg
  • 1/3 cup grated parmesan cheese
  • 1/4 cup freshly chopped basil plus more for serving; optional
  • 2 cups grated mozzarella cheese

Instructions 

Prep and roast the spaghetti squash

  • Preheat the oven to 400 degrees. Lay the spaghetti squash horizontally on a cutting board and using a sharp knife, remove the stem. Stand the spaghetti squash upright on the cut side and using a sharp paring knife, cut the squash in half from the top down one side at a time. You can also use a large knife and cut in half from the middle using a rocking motion, but I don't advise this if your squash is on the taller, large side. Turn the squash horizontally once more to cut through the stem to separate it if necessary.
    2 spaghetti squash
  • Scoop out the seeds and stringy insides with a large spoon, then use 1 tablespoon of the olive oil to brush over the cut side of the squash and season each squash half with salt and pepper to taste.
    2 tablespoons olive oil
  • Place the squash cut side down on the baking sheet and roast for 40-45 minutes or until tender. This will vary depending on the size of your squash. Remove from heat and shred the squash with a fork when it's cool enough to handle. You will have roughly 3 cups of squash.

Prepare the filling

  • While the squash cooks, prepare the filling. Heat a large skillet over medium heat. Add the remaining tablespoon of oil and the Italian sausage. Break up the sausage into small pieces with a wooden spoon and cook until golden brown and cooked through, about 5 minutes. Remove with a slotted spoon and place in a bowl, then drain all but 1 tablespoon of the grease.
    16 ounces Italian sausage
  • Add the onion to the skillet and cook 4-5 minutes until softened, then add the garlic and cook 30 seconds more. Add the sausage back to the pan along with the marinara sauce, and cook for 5-8 minutes longer. Remove from heat.
    1 onion, 3 cloves garlic, 2 cups marinara sauce
  • Place the ricotta cheese and egg in a medium bowl and stir until incorporated. Add the parmesan cheese and basil and stir until combined, then stir in the spaghetti squash.
    1 cup ricotta cheese, 1 large egg, 1/3 cup grated parmesan cheese, 1/4 cup freshly chopped basil

Assemble and bake the lasagna

  • Divide the ricotta mixture between the (4) spaghetti squash halves. You may have a bit leftover…it should not come all the way to the top.
  • Divide the sausage marinara mixture between the (4) squash halves and top with the grated mozzarella. Bake for 10-15 minutes or until bubbly and the cheese has melted. If you wish to brown the top, broil for about 1-2 minutes.
    2 cups grated mozzarella cheese
  • Remove from heat and garnish with additional freshly chopped basil if desired. Enjoy!

Notes

  • Pro tip:  Prep and cook the spaghetti squash 1-2 days in advance to make this meal go even more quickly!  You can also assemble them up to 1 day ahead and bake them when you’re ready.
  • You can roast spaghetti squash as per the instructions in the recipe card, or see my post how to cook spaghetti squash for more options.
  • Sub the Italian sausage for turkey sausage or your favorite ground meat.  You can also forgo the meat and use 16 ounces of chopped mushrooms.
  • Store spaghetti squash lasagna boats in the refrigerator for up to 3 days.

Nutrition

Calories: 977kcal, Carbohydrates: 48g, Protein: 45g, Fat: 70g, Saturated Fat: 29g, Polyunsaturated Fat: 8g, Monounsaturated Fat: 29g, Trans Fat: 0.01g, Cholesterol: 216mg, Sodium: 2060mg, Potassium: 1366mg, Fiber: 10g, Sugar: 20g, Vitamin A: 1984IU, Vitamin C: 24mg, Calcium: 654mg, Iron: 5mg

Nutrition is estimated using a food database and is only intended to be used as a guideline for informational purposes.

Did you try this recipe?Be sure to tag @flavorthemoments with the hashtag #flavorthemoments on Instagram so I can see what you made!

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