My creamy vegetarian spaghetti squash lasagna casserole is a nutritious twist on a classic dish that uses spaghetti squash instead of pasta. Spaghetti squash has a mild, slightly sweet flavor and is loaded with nutrients. Packed with protein and fiber, this dish will keep you feeling full and satisfied!
Lasagna is the ultimate comfort food. There's just something about that tower of noodles layered with tons of gooey cheese, meat, and homemade tomato sauce that's hard to beat!
I set out to make a lighter, vegetarian dish that would incorporate the flavors of lasagna that we know and love. My vegetarian spaghetti squash lasagna casserole uses nutritious spaghetti squash instead of pasta.
Spaghetti squash has a mild, slightly sweet flavor and when it’s cooked, the flesh falls away like ribbons or strands of spaghetti. It’s lower in calories and carbs than traditional pasta and is packed with nutrients like fiber and Vitamin C.
First, I bake the spaghetti squash in the oven. Then, I use a fork to scrape the flesh of the spaghetti squash into long, spaghetti-like strands.

Then, I mix the squash with creamy ricotta cheese and nutrient-packed spinach.
Next, I layer it with tomato sauce, reduced fat mozzarella and parmesan cheese. And finally, I bake it in the oven until it’s bubbling with cheesy goodness.
So if you're looking for healthy, vegetarian addition to your dinner table, go ahead and try this spaghetti squash lasagna casserole!
How To Make Spaghetti Squash in an Air Fryer
Traditionally, spaghetti squash is baked in the oven but you can also cook it in the air fryer! Compared to the oven, it's much faster in the air fryer. This is because the air fryer uses hot air to cook food quickly and evenly.
Also, air fryer helps to retain the vegetable's natural moisture and flavor. This results in a tender and flavorful spaghetti squash.
Read my post on how to cook spaghetti squash in the air fryer and get step-by-step instructions.

WANT MORE HEALTHY RECIPES?
Sign up for my email list and I'll send you my FREE Superfood Recipes eBook along with weekly recipes!
More Vegetarian Recipes
Recipe
Spaghetti Squash Lasagna Casserole
Equipment
Ingredients
- 1 large spaghetti squash (about 3 ½ pounds)
- 3 teaspoons olive oil, divided use
- 1 medium onion, chopped
- 3 cloves garlic, finely chopped
- 1 can (28 ounces) crushed tomatoes
- 2 teaspoons dried Italian seasoning
- ¼ teaspoon red pepper flakes
- 1 ½ teaspoons salt, divided
- ½ teaspoon pepper, divided
- 1 container (15 ounces) part skim ricotta cheese
- 1 large egg
- 1 package (10 ounces) frozen chopped spinach, defrosted and squeezed dry
- 6 ounces (1 ½ cups) reduced fat shredded mozzarella cheese, divided use
- ⅓ cup grated Parmigiano-Reggiano cheese
- Chopped parsley for garnish (optional)
Instructions
- Preheat oven to 400°F. Cut the squash in half lengthwise and remove the seeds. Brush the flesh with 1 teaspoon oil. Place them cut side down on a baking sheet lined with parchment paper. Roast in the oven until tender, about 40-45 minutes. Remove from oven and cool. When the squash is cooled, scrape the flesh with a fork so that it forms spaghetti-like strands. You should have a total of about 6 cups total.
- Meanwhile, make the sauce by heating 2 teaspoons oil in a large sauté pan over medium heat. Add the onion and garlic and cook 4-5 minutes until partially softened. Stir in the tomatoes, Italian seasoning, red pepper flakes, ½ teaspoon salt and ¼ teaspoon pepper. Simmer the sauce for 15-20 minutes until thickened.
- Mix the ricotta, egg, spinach, ½ cup mozzarella cheese, 1 teaspoon salt and ¼ teaspoon pepper together in a large bowl. Squeeze all of the liquid from the spaghetti squash and add it to the bowl (the squash releases a lot of water as it cooks so make sure to squeeze it well). Stir to combine all of the ingredients.
- Turn the heat on the oven down to 375°F. To assemble the lasagna, spread about 1 ½ cups of the sauce on the bottom of an 8x11-inch baking dish. Add the squash mixture on top and spread it out evenly. Spread the remaining tomato sauce over the top of the squash and sprinkle the remaining 1 cup mozzarella and Parmigiano cheese on top.
- Bake in the oven 35-40 minutes until bubbly and cheese is melted. Garnish with parsley. Let stand 10 minutes before cutting and serving.
Frank Favorito says
Love the concept but it's more like baked spaghetti than a lasagne. I love squash of all kinds and the addition of spiralized zucchini added great color. I've grilled spaghetti squash, then shredded it, added Italian sausage, mozzarella, parm, chopped button mushroom, and some sauce. Covered with tin foil, return to the grill for 15 min, just enough to melt the cheese, serve and enjoy.
plasterers bristol says
Great recipe this, one of my favorites. thanks for sharing.
Simon
Anonymous says
Just another note: This tastes even better the next day!
sonaliruder says
Yay, so glad to hear it! Thanks for sharing 🙂
Kelley @ Chef Savvy says
This spaghetti squash looks amazing! Love that it is healthy and delicious!
sonaliruder says
Thanks for stopping by, Kelley!
Anonymous says
Made this today and it was pretty good. Next time I will add some fresh basil to the cheese mixture, and will use Costco's white linen marinara sauce instead of the crushed tomatoes (less acidic). I wouldn't try to pass it off as lasagna for guests, but it's great for my family trying to eat healthy and low carb!
sonaliruder says
Fresh basil sounds like a great addition and of course you can substitute your favorite jarred tomato sauce. I've also done that when I'm pressed for time. Thanks for trying out the recipe!
nutritionalanatalie.com says
I absolutely love this idea! My family does lasagna every Christmas, and this is a way to make it lighter and add some veggies. Great idea.
sonaliruder says
It's definitely a great way to add some veggies and cut some calories! Thanks for stopping by 🙂
Cakespy says
Beautiful. I love spaghetti squash served pasta-esque but had never thought to lasagne-ify it!
sonaliruder says
Thanks! I'm going to start using that word- "lasagne-ify!" 🙂
Jennifer Lynn-Pullman says
I just had spaghetti squash for the first time recently and loved it.
sonaliruder says
It's so good, right? Thanks for stopping by Jennifer!
Anonymous says
Awesome post! Looks delicious!
sonaliruder says
Thanks for stopping by!
Katie (The Muffin Myth) says
This looks so great! Light, healthy, and delicious! And as it happens, I've got a nice big spaghetti squash sitting on my counter right now, so I'm thinking this could be dinner this weekend. Funny, I was looking at Recipe Redux just the other day and thinking of applying. I think you've inspired me to go for it!
sonaliruder says
You should definitely go for it, it's such a wonderful group! I hope you enjoy the recipe if you go ahead and try it. Thanks Katie!
Mira Cookinglsl says
I love the healthy resuscitation of lasagna! Perfect idea to use spaghetti squash! Pinning and will give the recipe a try soon!
sonaliruder says
Thanks Mira! I really hope you enjoy it if you go ahead and try it out 🙂
Erin says
I'm new to Recipe Redux also! I am so glad to join such a wonderful community all working towards the same goal! 🙂 This recipe looks delicious! I have never used spaghetti squash in lasagna, but what a clever idea! I will have to give this a go...after I recover from Thanksgiving, of course! 🙂
sonaliruder says
Thank you and welcome aboard too, it really is such a great community! Have a wonderful holiday!