Spaghetti Squash Lasagna Casserole

Name: Spaghetti Squash Lasagna Casserole
Prep time: 30 min
Cook time: 80 min
Total time: 110 min
Ingredients: 1 large spaghetti squash ((about 3 ½ pounds)); 1 teaspoon olive oil; 1 container (15 ounces) part-skim ricotta cheese; 1 large egg; 5 ounces frozen chopped spinach, (defrosted and squeezed dry); 1 1/2 cups part-skim shredded mozzarella cheese, (divided use); 1 teaspoons salt; 1/4 teaspoon black pepper; 1 jar (24 oz) jarred marinara sauce, like Rao's; 1/3 cup grated Parmigiano-Reggiano cheese; fresh parsley or basil for garnish, optional

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Indulge in all the comforting flavors of lasagna without the guilt with this creamy Spaghetti Squash Lasagna Casserole. A perfect blend of hearty tomato sauce, creamy ricotta cheese, and tender strands of spaghetti squash, this vegetarian dish is a low-carb twist on a classic favorite.

Spaghetti squash lasagna casserole in white baking dish.

This cheesy vegetarian spaghetti squash casserole is the epitome of comfort food meets healthy eating. It's one of my favorite spaghetti squash recipes and is a great recipe to try if you've never cooked this winter squash before.

With its creamy texture, savory tomato sauce, and gooey cheese topping, this spaghetti squash lasagna satisfies all your cravings while keeping your carb count low.

Jump to:

A Nutritious Lasagna
Doctor's Tips
Why You'll Love This Dish
Ingredients
How to Make Spaghetti Squash Lasagna Casserole Step-by-Step:
Chef's Tips:
How To Serve This Dish
Recipe FAQs
More Vegetarian Recipes
Recipe
Reviews

A Nutritious Lasagna

Lasagna is the ultimate comfort food. This creamy vegetarian spaghetti squash lasagna casserole is a nutritious spin on traditional lasagna. It has all the great flavors of traditional lasagna that we love but in a lighter and more nutritious package!

This comforting and light dish swaps out pasta for tender strands of spaghetti squash. But don't worry- this cheesy casserole will still satisfy your cravings thanks to the rich flavors and plenty of ooey, gooey cheese!

Spaghetti squash is a culinary rock star- low in calories, packed with nutrients, and incredibly versatile. Its spaghetti-like strands have a mild flavor and can be used in a wide variety of recipes, from main dishes to hearty side dishes.

The strands of squash are tossed with creamy ricotta cheese and chopped spinach. It’s then layered with tomato sauce, mozzarella, and parmesan cheese and baked in the oven until it’s bubbling with cheesy goodness. Packed with protein and fiber, this dish will keep you feeling full and satisfied.

Doctor's Tips

Spaghetti squash is packed with nutrients like beta carotene, vitamin C, and dietary fiber. It's a delicious low-calorie substitute for pasta for anyone watching their carb intake or trying to eat more vegetables.

Spaghetti squash is a nutritious and low-carb alternative to pasta dishes or rice. You can pair it with traditional tomato sauce and meatballs or serve it alongside creamy chicken or fish dishes to soak up the sauce.

Why You'll Love This Dish

Lightened up comfort food- This cheesy casserole is a healthier twist on traditional lasagna, offering all the comforting flavors without the guilt.
Nutritious- Spaghetti squash is rich in nutrients including beta carotene, vitamin C and fiber.
Low carb- This low-carb dish is perfect if you're watching your carb intake.
Versatile- Suitable for vegetarians and meat-lovers alike, offering options for customization with different fillings.
Easy to prepare- This light dish is the perfect weeknight meal, with simple ingredients and minimal prep time.
Family-friendly- This spaghetti squash bake is a hit with both kids and adults.
Make-ahead- Can be made ahead of time and reheated for a convenient meal on weeknights. It's also perfect for potlucks.

Ingredients

Ingredient notes and substitutions. See recipe card at the end of the post for full recipe details.

Spaghetti squash- use a large squash, around 3 ½ pounds
Marinara sauce- I use my favorite jarred marinara sauce to save time. If you want to make homemade sauce, try my the sauce in my spaghetti and meatballs recipe.
Ricotta cheese- I use part-skim ricotta for a creamy filling
Egg- holds the filling together
Spinach- I like to add spinach to the filling. Use a package of frozen spinach to make prep a lot easier. You can use fresh spinach but be sure to cook it and squeeze out all of the liquid before adding it to the filling.
Cheese- I use a mixture of mozzarella cheese and parmesan cheese in the casserole filling and on top.

How to Make Spaghetti Squash Lasagna Casserole Step-by-Step:

See recipe card at the end of the post for full recipe details.

1. Cook The Spaghetti Squash

First, you'll need to cook the spaghetti squash. The best way to do this is in the oven on a prepared baking sheet or in the air fryer. For more details, read my post on how to bake a whole spaghetti squash. To cook it in the air fryer, read my post on air fryer spaghetti squash. You can even cook it in the microwave.

2. Make The Filling and Assemble The Casserole

Steps for making spaghetti squash lasagna casserole.

Step 1- Prepare the casserole filling. In a large mixing bowl, mix ricotta cheese, egg, spinach, ½ cup mozzarella cheese, salt, and pepper.
Step 2- Squeeze any excess liquid from the cooked spaghetti squash and add it to the bowl. Mix it all together.
Step 3- To assemble the spaghetti squash lasagna, spread a thin layer of tomato sauce on the bottom of an 8x11-inch baking dish. Next, spread half of the squash and ricotta mixture on top.
Step 4- Spread half of the remaining tomato sauce on top of the squash. Then, top with another layer of squash and another layer of tomato sauce. Finally, sprinkle mozzarella and Parmigiano cheese on top.

Bake the spaghetti squash lasagna casserole in the oven at 375°F for 35-40 minutes until bubbly and golden brown. Let it rest for 10 minutes before serving.

Chef's Tips:

I use spinach in the filling of this vegetarian spaghetti squash recipe but you can add other veggies like bell peppers or mushrooms for a meaty texture
If you are not trying to keep this dish vegetarian, you can add ground turkey, beef or Italian sausage to this spaghetti squash lasagna.
You can use your favorite jarred marinara sauce or make homemade tomato sauce, if you have more time.
Add your favorite seasonings to bump up the flavors in this dish like chili flakes, Italian seasoning or fresh herbs like parsley or basil.
Make this casserole ahead of time and refrigerate or freeze it for a convenient weeknight meal.
For more details on how to cook spaghetti squash, read my post on how to bake a whole spaghetti squash in the oven. To cook it in the air fryer, read my post on air fryer spaghetti squash.

How To Serve This Dish

This creamy spaghetti squash lasagna casserole can be the star of your meal. It can be paired with a side salad, garlic bread or other crusty bread for a satisfying yet light dinner. For a low-carb side dish option, try my cheesy cauliflower bread.

You can also serve this casserole as a hearty side dish alongside your favorite protein, such as chicken or seafood. Its creamy texture and rich flavors complement a wide range of main courses. It's equally suitable for weeknight family dinners or for your holiday table.

Recipe FAQs

Can you freeze spaghetti squash lasagna casserole?

Yes, you can! Be sure to let it cool completely. Then, wrap it tightly in plastic wrap. It will keep for up to three months in the freezer. To reheat, remove plastic wrap and heat in a 375°F oven until warmed through and bubbling.