Creamy Spinach Spaghetti Squash Casserole combines fresh “squaghetti” noodles with sautéed spinach, red bell pepper, and garlic plus three kinds of cheese to create a rich, yet delicate dish.
Spaghetti squash noodles can be substituted in many other pasta dishes or served topped with regular pasta sauce saving you loads of carbs — so what’s not to love?!
Not only that, Creamy Spinach Spaghetti Squash Casserole is a cheesy vegetarian, keto-friendly, low-carb, gluten-free casserole. That covers about all the bases!

Creamy Spinach Spaghetti Squash Casserole
Confession time. The first time I made this recipe was my very first experience cooking spaghetti squash. Truth! I’m not sure why it’s took me so long to try this vegetable, but let me tell you that this first time will not be my last.
Unlike other veggies that you spiralize to make noodles, once cooked the flesh of a spaghetti squash can be separated into spaghetti-like strands (or squaghetti as I like to call it) simply by scraping it out with a fork.
One three-pound squash will make enough squaghetti to equal around a pound of pasta noodles — a great alternative when you are watching your carb intake!
How to Cook a Spaghetti Squash
Here are two easy methods for cooking spaghetti squash — either way works in this recipe:
In the oven:
- Cut the spaghetti squash in half length-wise.
- Use a large spoon to scrape and scoop out the seeds.
- Lay the squash cut side down in a baking dish and add 1/2-cup of water.
- Bake at 400-degrees about 35 minutes, or until fork-tender.
- Remove the squash from the pan and allow it to cool enough to handle.
- Use a fork to gently scrape all the flesh away from the rind/peel.
In the instant pot:
- Cut the spaghetti squash in half length-wise.
- Use a large spoon to scrape and scoop out the seeds.
- Add one inch of water to the Instant Pot and insert the steamer basket.
- Lay the squash in the basket (not in the water) and lock the lid and turn the valve to vent.
- Pressure cook for 5 minutes. When the pot beeps, hit cancel.
- Quick release the steam by carefully opening the vent.
- Remove squash and allow it to cool enough to handle.
- Use a fork to gently scrape all the flesh away from the rind/peel.
How to Make Creamy Spinach Spaghetti Casserole
This keto-friendly casserole is really simple to put together once the spaghetti squash has been cooked.

- Cook spaghetti squash and scrape out the flesh.
- Sauté diced onions and red bell pepper until tender, then add minced garlic and cook another minute until fragrant.
- Toss in fresh spinach and cook until wilted.
- Add a block of softened cream cheese and stir until melted.
- Gently stir in the spaghetti squash, then place the mixture in a lightly greased casserole dish.
- Top with mozzarella and parmesan cheese and bake until hot, bubbly, and the cheese has a golden crust.
More delicious vegetable recipes
- Zoodle Ratatouille is a composition of seasonal vegetables—zucchini, onions, sweet bell peppers, and tomatoes—cooked with olive oil and garlic.
- Broccoli Rice and Cheese Casserole is a delicious side dish for barbecue chicken, pork chops, or even meatloaf. A creamy rice dish using fresh broccoli and mushrooms, this casserole also uses both cheddar and Parmesan cheese for extra cheesy goodness!
- Grilled Corn and Mushroom Risotto starts with grilling fresh corn, mushrooms, and poblano chili peppers to create this creamy and hearty one-dish meal.
- Balsamic Roasted Parsnips and Carrots are topped with a feta cheese “salad” of lemon, parsley, and dried cherries.
- Roasted Spaghetti Squash with Marinara — low-carb spaghetti option!
- More side dish recipes!

To make this recipe you may need…
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Not totally necessary, but a pressure cooker is an easy way to cook spaghetti squash. I am thrilled with my new Mealthy MultiPot! I don’t know why I waited so long to get it and now can’t wait to experiment with all kinds of recipes. Not only that, I have a special coupon code just for my readers for a $10.00 savings off the purchase of $59.95 or greater. Just enter LIFELOVEANDGOODFOOD at checkout to get the discount!
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Creamy Spinach Spaghetti Squash Casserole Recipe
After removing the casserole from the oven, allow it to set for at least 15 minutes if you’d like to cut it into squares to serve like lasagna. To reheat the casserole, place a serving on a microwave-safe plate and heat for 1-1/2 minutes in the microwave.
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Creamy Spinach Spaghetti Squash Casserole

Creamy Spinach & Spaghetti Squash Bake with sautéed spinach, red pepper, garlic, and three kinds of cheese. Keto-friendly recipe, too!
Ingredients
- 1 3-pound spaghetti squash
- 1/2 cup water
- 1 teaspoon olive oil
- 1/2 red bell pepper, diced
- 1/2 cup diced sweet onion
- 1 clove garlic, minced
- 4 cups spinach, chopped
- dash of nutmeg
- 1 teaspoon salt
- 1/2 teaspoon pepper
- 8 oz. cream cheese, softened
- 1 cup mozzarella cheese
- 1/4 cup parmesan cheese
Instructions
- Preheat oven to 400 degrees.
- Slice spaghetti squash in half length-wise. Scoop out seeds and place cut side down in a glass baking dish. Pour 1/2 cup water into dish and bake for about 30-35 minutes. With a fork gently shred the pulp from the inside of the squash and set aside.Reduce oven heat to 375 degrees.
- On top of stove, heat olive oil in a large skillet over medium heat. Add the onion and red bell pepper. Sauté about 5 minutes, until tender. Add the garlic and cook until fragrant, about 1 minute.
- Add the spinach to the skillet and season with the nutmeg, salt, and pepper. Cook and stir until the spinach is wilted.
- Gently stir in the cream cheese until melted. Add the spaghetti squash and stir until combined.
- Pour the mixture into a casserole dish that is lightly coated with cooking spray. Top with the mozzarella and parmesan cheese. Bake at 375 degrees for 30 minutes, or until bubbly and cheese is lightly browned.
Notes
- After removing the casserole from the oven, allow it to set for at least 15 minutes if you'd like to cut it into squares to serve like lasagna.
- To reheat the casserole, place a serving on a microwave-safe plate and heat for 1-1/2 minutes in the microwave.
To cook the spaghetti squash in an instant pot:
- Cut the spaghetti squash in half length-wise.
- Use a large spoon to scrape and scoop out the seeds.
- Add one inch of water to the Instant Pot and insert the steamer basket.
- Lay the squash in the basket (not in the water) and lock the lid and turn the valve to vent.
- Pressure cook for 5 minutes. When the pot beeps, hit cancel.
- Quick release the steam by carefully opening the vent.
- Remove squash and allow it to cool enough to handle.
- Use a fork to gently scrape all the flesh away from the rind/peel.
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Nutrition Information:
Yield:
8Serving Size:
1Amount Per Serving: Calories: 229Total Fat: 15gSaturated Fat: 8gTrans Fat: 0gUnsaturated Fat: 5gCholesterol: 42mgSodium: 592mgCarbohydrates: 17gFiber: 5gSugar: 6gProtein: 10g
ABOUT SHEILA
Sheila Thigpen, author of Easy Chicken Cookbook and The 5-Ingredient Fresh and Easy Cookbook, is a recipe developer, food photographer, and food writer. She spent 20+ years as a business manager in the publishing industry before she retired in 2018 to focus on her passions — cooking, photography, and writing. Living near the beautiful Smoky Mountains, Sheila and her husband have two adult daughters and two fine sons-in-law, are active in their church, love to travel, and have a precious little granddaughter who has stolen their hearts. Follow Sheila on YouTube, Pinterest, Instagram, Facebook, and Twitter!
Chris
Thursday 7th of January 2021
Under pics diced onion is mentioned in the general instructions. It is not listed in the recipe ingredients or the actual recipe instructions though.
Sheila Thigpen
Monday 11th of January 2021
Chris, thank you for pointing out that omission! I've edited the recipe card to include the onion and proper instructions for when to add it to the recipe :)
Maryann
Saturday 11th of July 2020
This was amazing!! Instead of plain cream cheese I used onion chive cream cheese.
Jackson and Belle’s G
Monday 22nd of June 2020
My family really liked this. I discovered too late that we were out of spinach. So I chopped up one fresh eggplant and sautéed it with the other veggies. I then squished the eggplant up, because my daughter is not a fan of eggplant. I also added one seeded, diced jalapeño (supposed to be a mild version) to the sautéing veggies. I mixed about 2/3 of a cup of cheddar into the casserole and then topped with grated cheddar and grated Parmesan. I baked it for 30 minutes in 350. My family loved it, and my daughter never noticed the eggplant! Lol. I really didn’t taste the garlic or jalapeño in the dish. Next time, I will add 2 cloves of minced garlic and two minced, seeded jalepenos. I will also 3-4 dashes if Tobasco chipotle hot sauce. Great recipe!!!
Christina
Monday 30th of March 2020
Curious if you've tried freezing this. It made a whole lot of leftovers, and I don't know if I can eat it every day for the next week!
Sheila Thigpen
Monday 30th of March 2020
Christina, I have not tried freezing the leftovers, but I would think that should work. Cool completely and seal the leftovers tightly. I'd suggest thawing in the refrigerator before reheating, too.
Jamie
Tuesday 11th of February 2020
Just cooked this up! Added 97% fat free turkey! I’m doing weight watchers and this came out to five points with the ingredients that I used! Can’t wait to dig in, thank you so much for an awesome recipe!!