Spaghetti Squash Lasagna

This Spaghetti Squash Lasagna has layers of low-carb, filling spaghetti squash, bright cilantro, and homemade tomato sauce, with rich, creamy mozzarella and part-skim ricotta. It’s healthy, vegetarian, hearty and flavorful!

We love lasagna at my house, and my family has asked me to make this particular lasagna over and over again. The crispy kale and slightly caramelized onions bring out the richness of the perfectly succulent spaghetti squash, all rounded out by melted cheese and highlighted with notes of nutmeg and cilantro. It’s comforting, satisfying, and unique in all the best ways!

I can’t get over spaghetti squash ever since my twice-baked spaghetti squash recipe was such a hit! This recipe joins the squash hall of fame with my baked acorn squash halves, vegan chili  and this savory butternut squash carrot tart.

Professional Tips

• Buy fresh mozzarella and a high quality asiago. Fresh mozzarella has more flavor than the pre-shredded or low-moisture versions. More flavor means you use less cheese for the same impact, which equals fewer calories and better taste!
• Use flat noodles. I like to use flat lasagna noodles because they allow you to layer in more vegetables in the same amount of space. If you cannot find flat noodles, you might only be able to make two layers.
• Thicken your tomato sauce. I thickened my tomato pasta sauce by using an additional can of diced tomatoes and cooking the sauce until it had the consistency of a thick stew. Spaghetti squash has a high water content. Therefore, you need a thicker sauce to make the lasagna more cohesive.
• Roast the spaghetti squash in advance. Roast, fluff and separate with a fork, cool and store the squash in the refrigerator up to 3 days in advance. The side benefit of this is that some of the liquid will drain. Leave it out of your lasagna for a thicker dish.

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Ingredients

• Spaghetti Squash: Spaghetti squash are a Winter squash, which means in the Fall & Winter they will contain less water and have a deeper, richer flavor. 
• Ground Nutmeg: This recipe is written for freshly ground nutmeg. If you don’t have fresh nutmeg, I suggest omitting it. The flavor of pre-ground nutmeg is very different and it isn’t the star of the show here.
• Black Pepper & Kosher Salt
• Onion: I recommend using a yellow or sweet onion for this recipe. White onions tend to be a bit too sharp.
• Garlic: I recommend using fresh garlic for this recipe. It will not have the same flavor if you substitute this for garlic powder. You can use jarred, minced garlic for an easy shortcut. 
• Kale: I like to use Tuscan kale, also called Lacinato kale, in this dish. These are the flat, rounded kale leaves as opposed to the curly leaves with frilled edges. Either taste delightful.
• Cilantro: Try a variety of fresh herbs in this recipe. Cilantro adds a bright, fresh taste to this recipe that I think you will love.
• Ricotta cheese: I tend to use part-skim ricotta rather than anything with a lower fat content as the texture can become a bit grainy.
• Mozzarella: I recommend using freshly shredded mozzarella cheese. Pre-grated cheeses have anticaking agents that can prevent them from melting fully. You will achieve a much better texture with cheese you shred yourself. Buy extra so you can make some Heirloom Tomato and Mozzarella Salad as an appetizer!
• Asiago cheese: Be sure to choose a vegetarian asiago, if you are concerned.
• Whole-Wheat Lasagna Noodles
• Tomato Sauce: You can either purchase a thick variety of tomato sauce or you can make this excellent homemade marinara sauce and add some diced tomatoes.

See the recipe card for full information on ingredients and quantities.

Variations

• Swap out the squash: I have also made this recipe by slicing and roasting summer squash and zucchini on baking sheets before assembling the lasagna. I season each with dried Italian seasoning and just a touch of salt. This cooks out the moisture, so the final lasagna will be even more flavorful. Use my Vegetable Lasagna as inspiration!
• Extra Vegetables: Add vegetables like eggplant or spinach to the existing recipe for a more vegetable-forward dish. I would suggest slicing and roasting the eggplant first for the best texture. You could also use collard greens, but be aware they have a bit more of a bite! {I talk about that more in my post on Collard Green Salad with Vidalia Onion Peach Glazed Chicken.}
• Different Cheese: Try adding cottage cheese in addition to the ricotta cheese for an extra rich and creamy dish. Start by substituting half the ricotta.

How to Make Spaghetti Squash Lasagna

Further details and measurements can be found in the recipe card below!

Roast and season the squash: 

Step 1: Preheat the oven to 425°F. Line a rimmed baking sheet with parchment paper.

Step 2: Halve your spaghetti squash, scoop out the insides, and place the halves cut side up on your baking sheet; drizzle with olive oil and coarse kosher salt. Flip them over and drizzle with more olive oil and salt.

Step 3: Bake in your preheated oven until the skin easily gives when you poke it with a fork. It will feel soft and will indent. This baking time will vary drastically by the size of your squash; 30-60 minutes.

Step 4: Grip the squash with tongs and scrape out the spaghetti squash strands with a fork into a medium bowl. Repeat with all remaining squash halves.

Step 5: Season generously with olive oil, kosher salt, fresh ground pepper and fresh ground nutmeg (omit the nutmeg if you only have the pre-ground type). I like to season the squash in batches; fluffing with a fork to toss and coat.

Prep and assemble your lasagna:

Step 6: Preheat the oven to 350°F.

Step 7: Mix fresh, chopped cilantro with the ricotta in a medium bowl and set aside. 

Step 8: Heat a large skillet over medium heat. Add about 1 tablespoon olive oil, swirl to coat. Sauté onions and garlic until onions are translucent. Remove from the skillet and set aside. Add a little bit more olive oil and sauté the kale until it is limp and cooked through. Add kale to onions and mix.

Step 9: If using dried noodles, cook until al dente (still has a little chew to the center). Drain and rinse in cold water to stop the cooking process. Drizzle with a little olive oil to keep them from gluing themselves together. Place all your ingredients out around your 12x7x4 baking dish. 

Step 10: Start assembly by spreading a thin layer of sauce on the bottom of the dish and place 3 overlapping lasagna noodles on it.

Step 11: Spread about a third of the ricotta mixture on the noodles with a rubber spatula. 

Step 12: Next add your spaghetti squash being careful not to scoop out too much water that has drained to the bottom of your bowl. 

Step 13: Next sprinkle 1/3 of the onion/kale mixture over the squash. It’s easiest to do this with your hands.

Step 14: Top the vegetables with sauce. 

Step 15: Finally, add a layer of mozzarella cheese and asiago. 

Step 16: Repeat until the pan is filled, ending with cheese. 

Step 17: Bake the lasagna for 50 minutes or until bubbling. Cool 10-20 minutes before serving.

Frequently Asked Questions

Before You Go

I hope you enjoyed this professional chef-tested recipe. Check out our other delicious, filling vegetarian recipes or make a ground beef or ground turkey lasagna variation using my Ultimate Lasagna Recipe!