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If you’re looking for a veggie-packed twist on comfort food, look no further than this mouthwatering masterpiece—Pesto Spaghetti Squash. This Italian-inspired recipe combines tender spaghetti-like strands of squash with herbaceous pesto sauce, rich marinara, and three types of cheeses. Simple to prepare with 8 basic ingredients, this casserole is equal parts indulgent and deliciously wholesome.
“I made this last tonight! I’m a lasagna fanatic, and this pesto with spaghetti squash version is delicious! You’re a genius!”
– KAYLA
Update: This recipe was originally published in January 2020. I made edits to the article below to include more information about making this spaghetti squash casserole with pesto at home.
Hi, friends! If you love lasagna and spaghetti casseroles, it’s my pleasure to introduce you to today’s dish, which will surely have you saying “Mamma Mia” with every single bite:
Table of Contents
About this pesto spaghetti squash
With the ideal combination of satisfying textures and deliciously cozy, vibrant flavors, this pesto spaghetti squash casserole will have everyone reaching for seconds.
Picture this: delicate strands of spaghetti squash layered with creamy basil pesto sauce infused ricotta, rich tomato marinara sauce, melty mozzarella, and freshly grated parmesan cheese. Finished with a generous sprinkling of fresh sweet basil and more cheese, this pesto with spaghetti squash is robust and rich in flavor – and also lower in carbs than the traditional Italian dish.
And the best part (aside from the taste)? This recipe is super simple to prepare with just 8 ingredients and 20 minutes of hands on preparation.
Whether you’re hosting a dinner party or simply looking to feed your family a vegetable-packed, deliciously cozy meal, this spaghetti squash with pesto sauce is feast for your eyes AND your tastebuds!
Why you’ll love this recipe!
There’s so much to love about this pesto spaghetti squash recipe:
- Simple to Make with Easy-to-Find Ingredients. This recipe relies on simple ingredients and straightforward steps to ensure dinner success.
- Wholesome yet Super Satisfying. Swapping out classic noodles for spaghetti squash ensures this pesto and spaghetti squash casserole is the ideal mix of savory, hearty, and light.
- Cozy and Flavorful. Silky spaghetti squash meets vibrant pesto, creamy ricotta, and plenty of melty cheese.
- Customizable. This spaghetti squash recipe is incredibly easy to customize to suit your taste preferences and/or whatever you have on hand. Add more garlic, swap the mozzarella for burrata, nix the basil pesto in favor of tomato pesto, and so on.
- All Season Recipe. While the fresh basil and pesto are perfect for summer, the spaghetti squash works great in winter and fall—ensuring you can get your comfort food fix regardless of the season.
Ingredients for spaghetti squash pesto
- Spaghetti Squash. This yellow squash is the star of the show, so be sure to look for one that’s firm with smooth, yellow skin for the best flavor.
- Marinara Sauce. Make sure to use a good-quality brand of red tomato sauce or make your own marinara sauce for the best flavor.
- Fresh Basil. Vibrant with a delightful aroma, basil leaves lend a slightly peppery flavor and subtle fresh sweetness.
- Ricotta Cheese. Grab whole milk ricotta cheese for the best texture.
- Basil Pesto Sauce. You can use homemade basil pesto sauce or store-bought, depending upon your preference.
- Garlic. Fresh garlic lends a subtle punch of irresistible flavor. Be sure you use fresh cloves of garlic and mince them yourself for the best flavor. That minced stuff in a jar is convenient, but it definitely lacks the same flavor as the fresh stuff.
- Parmesan Cheese. Freshly grated parmesan cheese lends a salty, slightly nutty finish.
- Mozzarella Cheese. Fresh mozzarella lends richness and the perfect touch of cheesy indulgence. Swap: You can use burrata if you’re looking for even more richness.
Recipe variations
- Pesto Variations. If you’re looking to shake things up, switch out the basil pesto and use sun dried pesto or pesto sauce with arugula instead.
- Red Sauce Swap. Take things in a different direction by swapping out the marinara and using your favorite red sauce instead. Vodka sauce, roasted red pepper sauce, short rib bolognese sauce, and spaghetti meat sauce will all be delicious here.
- Make it Classic. If you prefer real spaghetti noodles over spaghetti squash noodles, simply nix the squash and use spaghetti pasta instead.
If you’ve got leftover pesto sauce, put it to good use in these delicious recipes next: Pesto Sausage and Veggies, Tortellini Pesto, and Arugula Pasta Recipe.
Chef expert tips for perfect results every time!
- Choose the Best Squash. Since spaghetti squash is the main ingredient, you’ll want to be sure to grab a good looking one at the grocery store. When shopping, select a squash that feels heavy for its size with deep yellow coloring and a hard exterior.
- Use Good-Quality Sauces. The pesto sauce and tomato sauce are pretty key ingredients in this recipe, so make sure you use high-quality brands or use homemade for the best taste.
- Roast the Spaghetti Squash Until Tender. To get perfectly tender spaghetti-like strands of squash, roast the squash until the flesh is soft and it easily separates into strands when you scrape it with the tins of a fork.
- Drain Well. Spaghetti squash is a watery vegetable. Make sure you squeeze the spaghetti squash strands dry using a kitchen towel or paper towels before assembling the casserole in the baking dish.
- Garnish Before Serving. Garnishes are more than just decorative flare – they can take your final dish from ho-hum to oh-yum – so consider finishing your pesto squash with a generous dusting of parmesan, fresh basil leaves, ground black pepper, and crushed red pepper flakes before serving.
Step-by-step photos: making this recipe at home
If you’re looking for the detailed measurements and full recipe instructions, please scroll down to the bottom of the page.
FAQs: frequently asked questions
You’ve got questions? I’ve got answers! If you have a question you don’t see listed below, please drop them in the comments section. I’m happy to help when I can!
What is spaghetti squash casserole?
Spaghetti squash casserole is an easy and healthier version of hearty classic spaghetti casserole. A flavorful tomato sauce is layered with cooked spaghetti squash and cheese, and then baked in the oven until hot and bubbly. Squash casserole can be made with meat sauce or plain tomato sauce for vegetarians.
Can I use store-bought pesto?
Absolutely! You can use homemade or store-bought basil pesto sauce here – just make sure to select a good-quality brand if using store-bought.
How to cut a whole spaghetti squash?
Spaghetti squash needs to be cut into two halves before baking or roasting.
- Spaghetti squash has a very tough exterior, so I recommend using a sharp paring knife to make small incisions, lengthwise, along the side of the squash where you plan to cut it.
- Microwave the squash for 3-5 minutes to help soften the exterior before cutting. Allow the squash to cool until no longer hot to the touch.
- Place squash on a clean work surface and use a sharp knife to cut the squash lengthwise, from the top to the base, along the same line of incisions you made previously.
- Use a large spoon or ice cream scoop to scoop out the seeds and discard them before baking.
How do I know when the spaghetti squash is done cooking?
Spaghetti squash is done roasting in the oven when the flesh easily separates into spaghetti-like strands when you scrape it with a fork.
Tips for perfectly roasted spaghetti squash:
- Bake the squash at moderately high heat (400 degrees F) for the most flavorful, slightly caramelized strands of squash.
- Avoid roasting cut side up or water will pool inside the squash.
- Check the squash for doneness. Smaller spaghetti squash will take around 30 minutes, while large squash can take up to 55 minutes.
How to prevent watery spaghetti squash casserole?
While spaghetti squash is a wonderful alternative to pasta, isn’t an actual replacement or true substitution for pasta. Spaghetti squash has a tendency to get a bad reputation because it does release water when cooked.
To prevent watery spaghetti squash, it is imperative you place the cooked strands of spaghetti squash in a kitchen or tea towel and squeeze out the excess water before proceeding with assembling the casserole. Also, make sure you are properly cooking the spaghetti squash (as noted above).
Until next week, friends, cheers – to better comfort food!
Cheyanne
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More spaghetti squash recipes!
Pesto Spaghetti Squash
Equipment
- 1 Rimmed Baking Sheet
- 2 Medium Mixing Bowls
- 1 9×13-inch Casserole Dish
Ingredients
- 1 large Spaghetti Squash (about 4 to 4 ½ pounds) – halved lengthwise and seeds removed (SEE NOTES)
- 1-2 TBS Extra Virgin Olive Oil – to taste
- to taste Kosher Salt & Ground Black Pepper
- 3 Cups Thick Marinara Sauce (SEE NOTES)
- ¼ Cup Fresh Basil Leaves – thinly sliced, plus more for garnish
- 2 Cups Whole Milk Ricotta Cheese
- ½ heaping Cup Basil Pesto Sauce – homemade or store-bought
- 1 clove Garlic – finely chopped
- 2/3 Cup Freshly Grated Parmesan Cheese – DIVIDED
- 8 ounces Fresh Mozzarella – torn or shredded
Instructions
- Roast the Spaghetti Squash: Arrange oven rack to the center position and then preheat the oven to 400 degrees F. Line a rimmed baking sheet with parchment paper for easy clean up. Rub the cut sides of the squash with olive oil and season to taste with salt and pepper. And then place the squash, cut side down, on the prepared baking sheet. Transfer to the oven and bake for 40-50 minutes, or until the squash is tender and easily pierced with a fork. When squash is cooked and cool enough to handle, use a fork to gently scrape out the strands of squash and discard squash “shells”. Transfer the squash strands, in batches, to a kitchen towel or tea towel. Squeeze the excess water out of the spaghetti squash. Transfer to a bowl and set aside. Keep the oven at 400 degrees F.
- While the Squash Roasts, Make the Pesto Ricotta Mixture: In a medium bowl, combine the ricotta with the pesto, garlic, and 1/3 cup parmesan cheese. Season with ¼ teaspoon salt and 1/8 teaspoon ground black pepper. Stir to combine and then set the bowl aside.
- Flavor the Marinara Sauce: Stir the fresh basil into your marinara sauce. Give the sauce a taste and adjust it to suit your tastebuds. Then set it aside.
- Layer the Spaghetti Squash with Pesto, Marinara, and Cheese: Grease 9×13-inch casserole dish. Spread ¾ cup of the tomato sauce onto the bottom of the dish. Top with half of the cooked spaghetti squash noodles. Top with half (1 ½ cups) of the ricotta mixture followed by half (1 ¼ cups) of the remaining tomato sauce and half (4 ounces) of the mozzarella cheese. Repeat with the remaining squash noodles, ricotta and tomato sauce. Sprinkle with remaining mozzarella cheese and remaining 1/3 cup parmesan cheese.
- Bake Pesto Spaghetti Squash in Oven: Transfer the casserole to the preheated oven and bake for 25-30 minutes or until the top of the casserole is browned and bubbly.Remove from oven and place the casserole dish onto a wire rack. Let cool for 5-10 minutes before garnishing and serving.
- Serve Pesto Spaghetti Squash Casserole: Garnish the top of the spaghetti squash with more parmesan cheese and fresh basil, if using. Enjoy immediately.
Notes
- Squash: You can use one large spaghetti squash or two smaller ones. Just make sure overall your squash measures roughly 4 to 4 ½ pounds. If you meal prep and have cooked spaghetti squash on hand, the equivalent is about 9 cups of cooked spaghetti squash strands.
- To make the squash easier to cut in half: Use the tins of a fork to poke the outside of the squash a few times. Place the squash on a microwave safe plate and microwave on high for 3-5 minutes to soften the exterior before cutting.
- If you like things spicy, add a teaspoon of crushed red pepper flakes to your marinara sauce.
- Need protein? Feel free to add cooked, shredded chicken, turkey, ground beef or ground pork to the casserole! Or, if you prefer meat, try making this with homemade Bolognese instead of the tomato sauce.
- Gluten-free? Make sure your marinara sauce is gluten-free.
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Need to Scale the Recipe? Hover your mouse over the number of servings in the recipe card. You’ll see a sliding scale pop up, you can use that to scale the recipe up or down as needed.
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Got questions? I’ve got answers! If you ever run into an issue, have a question, or need any clarification – please feel free to drop them in the comments section. I’m happy to help when I can!
Nutrition
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Katerina
This dish is absolutely divine, Cheyanne! I am loving all your photos – absolutely droolworthy. Thanks so much for sharing, I can’t wait to make this again!
Dawn
This tastes amazing! What a great comfort dish that is also healthy. Great way to start the New Year resolutions.
Kayla
I made this last tonight! I’m a lasagna fanatic, and this pesto with spaghetti squash version is delicious! You’re a genius!
Jennifer @ Seasons and Suppers
I clearly need to be picking up some spaghetti squash ASAP! This looks fabulous and I love it with the pesto. marinara and all that cheese goodness 🙂