Everything you love in lasagna with a simple noodle swap. This spaghetti squash lasagna is full of flavor, and comforting deliciousness yet is gluten free AND low in carbs. Twirl up some lasagna today!
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How to Cut and Cook Spaghetti Squash
To get our lasagna noodles ready, we’ll need to slice and bake our squash. This can be done in the oven or microwave depending on your preference:
- To cut spaghetti squash for baking: Remove the top and bottom (this makes it easier to slice), then slice the squash through the middle lengthwise.
- To bake: Place squash flesh side down on a baking sheet, and bake at 400 F for 30-40 minutes.
- To microwave: working with the squash whole, pierce the skin with a fork. Microwave on high for 5 minutes, then flip and microwave again. Let the squash sit for 5 minutes before slicing.
Psst–For more tips and tricks, check out my how to cook spaghetti squash guide.
Spaghetti Squash Lasagna Ingredients + Swaps
The ingredient list for spaghetti squash lasagna is similar to traditional lasagna. Here are a few things to keep in mind:
- The sauce: I don’t recommend just any sauce for this dish, as most sauces contain loads of sugar. Read labels carefully if opting for storebought products–Rao’s Homemade or my keto spaghetti sauce are my go-to’s. You can also substitute in your favorite sauce, think pesto or keto alfredo sauce ala spaghetti squash alfredo.
- The meat: Italian sausage is my lasagna go-to. Feel free to use ground turkey, shredded chicken, or keto meatballs instead.
- The cheese: We love a combo of shredded mozzarella and grated parmesan.
- The veggies: The only veggies here are our spaghetti squash noodles. You can always mix in your faves, such as sauteed spinach or sauteed mushrooms.
What Other Veggies Can You Use for Keto Lasagna
Still not sold on the wonders of spaghetti squash? Don’t worry — there are tons of veggie noodles out there to suit every taste.
- Zucchini lasagna – My favorite swap for this recipe is zucchini noodles or zoodles. They bake up faster than spaghetti squash and contain fewer calories and carbs.
- Cabbage lasagna – The easiest way to make keto lasagna–just shred the cabbage, steam it, and use it instead of spaghetti squash.
- Eggplant lasagna – Same concept as zucchini lasagna, but with julienned slices of eggplant instead.
- Cauliflower lasagna – The newest addition to my lasagna collection, I use roasted cauliflower florets and toss all the ingredients together. It comes together quickly and easily, although the noodles are very different from traditional lasagna.
How to Make Spaghetti Squash Lasagna
After you’ve sliced, and cooked the spaghetti squash, your hard work is done! Simply toss everything together, assemble, and let your oven do the rest:
Make the red sauce: In a large pan, brown the meat and set it aside on a paper towel-lined plate. Remove excess grease with tongs and a paper towel, then saute the onion and garlic in a splash of olive oil. Once translucent, remove from heat and add the spaghetti sauce.
Make the white sauce + filling: In a large bowl, combine all your white sauce ingredients. Mix the meat sauce, white sauce, and cooked and shredded spaghetti squash together in a large bowl.
Stuff + bake: You can either stuff the filling back into the spaghetti squash boats, or a casserole dish for a spaghetti squash casserole. Then top with cheese and bake in your preheated oven.
Storing, Freezing, and Reheating Spaghetti Squash Boats
Healthy lasagna that’s easy to reheat all week long? You’ve got it. Here’s how to keep your sauce saucy and your cheese melty for delicious leftovers.
- Storing: You can store baked squash in the fridge for up to four days in an airtight container. Leave the fresh basil on the side, and top your slices after reheating them.
- Freezing: You can freeze this spaghetti squash lasagna–I suggest placing your noodles in a resealable baggie (not the squash boats) before freezing.
- Reheating: The high water content of the squash will water down your sauce when stored in the fridge, so be sure to give your spaghetti squash lasagna a good stir after reheating.
More Pasta Substitutes to Love
- Almond Flour Pasta
- Butternut Squash Noodles
- Zucchini Ravioli
- Spaghetti Squash Pad Thai
- Cauliflower Mac and Cheese
Spaghetti Squash LasagnaPrint Recipe Pin Recipe
- 6-8 Pound Large Spaghetti Squash Flesh included. This should be about 2 small spaghetti squash, or 1 large.
- Mild Tasting Oil (see notes below)
- 1 Pound Italian Sausage casing removed
- 1 Yellow Onion chopped finely
- 4 Garlic Cloves minced
- 2 – 24 Ounce Jars of Keto Spaghetti Sauce OR, no sugar added marinara
- 2 Teaspoons Oregano dried
- 1 Teaspoon Fresh Basil dried
- 1 Teaspoon Kosher Salt
- 1/2 Teaspoon Black Pepper
- 32 Ounces Ricotta Cheese
- 1 Large Egg
- 2 Cups Parmesan Cheese divided
- 4 Cups Mozzarella Shredded divided
- 1 Cup Fresh Basil Chopped
- Preheat oven to 400 F, option to line a rimmed baking sheet with parchment paper.
- Cut spaghetti squash in half and scoop the seeds from the center using a spoon. Place cut side down on the rimmed baking sheet, and bake in preheated oven for 30-40 minutes, or until your squash is fork-tender. Once the squash is cool enough to handle, run a fork through the flesh to form "noodles".
- While squash is in the oven, cook Italian sausage in a large skillet over medium-high heat, breaking it up with the back of your spoon as it cooks. Cook until no pink is left. Place cooked meat on a paper towel-lined plate and set aside. Carefully remove excess fat from skillet using paper towels and tongs. Add vegetable oil and yellow onion to your pan, and saute until soft, about 10 minutes. Add minced garlic and cook until fragrant, about 2 minutes. Remove skillet from heat and stir in the pasta sauce and meat.
- In a large bowl, combine dried oregano, basil, salt, black pepper, ricotta cheese, and egg. Plus 1 cup of parmesan and 2 cups of mozzarella. Add the red sauce and noodles to your ricotta combo, and stir to combine.
- You can bake your lasagna 1 of 2 ways:1. In the spaghetti squash shell. To do this, you'll want to scoop the filling into the spaghetti squash boats and sprinkle the remaining cheese (1 cup parmesan, 2 cups mozzarella) on top. There will be more filling than you can fit in the shells (I like to bake this in a separate 8×8 casserole dish). Bake in preheated oven for 30 minutes.2. In a casserole dish. Spread the filling into a 9×13 pan in an even layer. Sprinkle the top with remaining cheese, (1 cup parmesan, 2 cups mozzarella). Bake in preheated oven for 45 minutes.
- You'll know your lasagna is done once the top is golden brown and the dish is heated through. Allow lasagna to cool slightly before serving, and enjoy!