Low-Carb Spaghetti Squash Lasagna Recipe

Indulge in the comforting flavors of lasagna without the pasta. This low carb Spaghetti Squash Lasagna Casserole is naturally gluten-free, easy to make, and a lighter take on a classic family favorite. It combines savory Italian sausage, creamy ricotta, and melty mozzarella layered with tender spaghetti squash for a satisfying, vegetable-forward dinner.

A longtime reader favorite, this Spaghetti Squash Lasagna is one of those recipes I return to again and again. It proves that you can enjoy all the cheesy, tomatoey satisfaction of traditional lasagna while cutting the carbs and adding more vegetables to the plate.

While I still love a classic pasta night, I don’t miss the noodles in this version. The cooked spaghetti squash provides a light, slightly sweet base that pairs perfectly with spicy Italian sausage, ricotta mixed with a hint of Parmesan and egg, and a generous topping of mozzarella. It’s cozy comfort food that doubles as a practical weeknight meal or a simple option for meal prep.

This recipe works well for families, and you can easily adapt it to be vegetarian, dairy-free, or to use different proteins or vegetables depending on what you have on hand.

Love low carb lasagnas? Try other noodle-less options like zucchini lasagna or stuffed spaghetti squash variations for more healthy, flavorful meals.

Why You Will Love this Recipe

• All the rich flavors and cheesy layers of traditional lasagna but with fewer carbs.
• Filling and satisfying portions that keep you full without heavy pasta.
• Balanced with protein, fiber, and healthy fats—suitable for Keto, 21 Day Fix, and many macro-based plans.
• Great for meal prep: it reheats nicely and often tastes even better the next day.
• Highly customizable—swap proteins, add extra vegetables, or use different cheeses to suit your preferences.

Ingredients

For exact amounts, see the recipe card below. In general you’ll need:

Olive oil cooking spray (or a little olive oil), spicy Italian turkey or chicken sausage (casings removed), a small diced onion, minced garlic, part-skim ricotta (or cottage cheese), an egg to bind the ricotta, tomato sauce or no-sugar-added marinara, one medium cooked spaghetti squash (about 4 cups cooked), shredded mozzarella, grated Parmesan, fresh basil, and salt and pepper to taste.

How to Make Spaghetti Squash Lasagna

Step-by-step instructions are below. The method is straightforward: prepare the squash, cook the filling, layer the casserole, and bake until bubbly.

Step One: Prepare the Spaghetti Squash

• Cook the spaghetti squash using your preferred method: oven, microwave, Instant Pot, or slow cooker. Once cooled, remove seeds and scrape the flesh with a fork to create “spaghetti” strands.
• To prevent a watery casserole, squeeze the cooked strands in a clean kitchen towel or paper towels to remove excess moisture. Season lightly with salt and pepper.

Step Two: Make the Filling

• Sauté diced onion in a skillet sprayed with olive oil until translucent. Add sausage, breaking it up and cooking until browned and cooked through. Stir in garlic for the final minute and remove from heat.
• In a bowl, combine ricotta with an egg, grated Parmesan, and a pinch of black pepper to make the ricotta mixture.

Step Three: Assemble the Lasagna

• Preheat oven to 350–375°F (190–190°C). Lightly grease a casserole dish.
• Spoon half the tomato sauce into the bottom of the dish, then add the cooked sausage in an even layer.
• Top the sausage with the cooked spaghetti squash, spoon over the remaining sauce, and scatter fresh chopped basil.
• Spread the ricotta mixture over the top and finish with shredded mozzarella and a sprinkle of Parmesan.

Step Four: Bake

• Bake until the cheese is melted and bubbly, about 15–20 minutes. If you want a golden top, broil on low for a few minutes—watch closely so it doesn’t burn.
• Let the lasagna rest a few minutes before serving. If excess liquid has collected, spoon off or drain carefully from a corner.
• Garnish with fresh basil and serve warm.

Substitutions + Variations

This dish is highly adaptable—tailor it to your dietary needs or whatever’s in the fridge.

• Replace Italian sausage with lean ground beef, ground chicken, or a plant-based ground meat.
• Swap ricotta for cottage cheese, or use vegan ricotta for a dairy-free version.
• Make it vegetarian by omitting the meat and adding sautéed spinach, mushrooms, or zucchini.
• If you don’t have prepared sauce, use a can of crushed tomatoes seasoned with Italian herbs.
• Turn each spaghetti squash half into a lasagna boat: layer meat, sauce, and cheese directly in the squash shells and bake.

Recipe FAQs

Meal Prep and Storage

To prep ahead:

• Assemble the lasagna and refrigerate, covered, for up to 24 hours before baking.
• Or prepare sauce, cooked squash, and the meat mixture up to three days ahead and assemble on the day you plan to bake.

To store:

• Cool leftovers to room temperature, then store in an airtight container in the refrigerator for 3–4 days.

To freeze:

• Wrap portions or the whole dish tightly with plastic wrap or foil and place in an airtight container or freezer bag. Freeze for 2–3 months.

To reheat:

• Reheat in a 350°F oven until warmed through—about 15–20 minutes for individual servings, 30–40 minutes for a whole dish.
• Microwave individual portions for 2–4 minutes until hot. Thaw frozen portions overnight in the refrigerator before reheating for best results.

More Healthy Spaghetti Squash Recipes

Try other healthy spaghetti squash meals such as Mediterranean stuffed squash boats, shrimp scampi with spaghetti squash, or simple spaghetti squash with meat sauce for more low-carb dinner ideas.

If you try this recipe, please leave a review—feedback helps others discover and enjoy this lighter lasagna alternative.