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Keto Spaghetti Squash Casserole with Alfredo Sauce

4.90 from 959 votes
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This Keto Spaghetti Squash Casserole with creamy Alfredo sauce is calling all pasta lovers!

Crunchy vegetable spaghetti smothered with a gluten-free creamy garlic sauce topped with broiled cheese and only 6 grams of net carbs. A delicious, comforting keto recipe that the whole family will love.

Are you ready for fall recipes welcoming spaghetti squash as the new keto vegetable into your plate? But first, let’s talk about spaghetti squash.

What’s Spaghetti Squash?

Spaghetti squash is a winter vegetable also known as vegetable spaghetti or noodle squash.

Its name came from its yellow-orange flesh that forms spaghetti-like strands when the cooked flesh is pulled apart with a fork.

Spaghetti squash recipes are one of these comforting meals, perfect for replacing a lasagna!

Creamy garlic Spaghetti squash casserole

Is spaghetti squash keto-friendly?

Yes, you can eat spaghetti squash on a keto diet. It is a very low-carb and low-calorie vegetable, with only 5.5 grams of net carbs and 31 kcal per cup.

It means it has a similar amount of carbs as its keto vegetable friends: cooked eggplants or Brussels sprouts.

Spaghetti squash is an amazing vegetable to create tasty keto recipes for pasta lovers.

In fact, the spaghetti strands from this squash are firm, long, tasteless, and truly mimic the texture of real spaghetti pasta.

How To Make Spaghetti Squash Casserole

It is pretty easy to make a baked spaghetti squash casserole, read the short instruction below or read my detailed guide on how to cook spaghetti squash.

First, you need to bake your squash to release the vegetable spaghetti. Let’s see how to cook spaghetti squash!

There are a few different ways to cook spaghetti squash depending on:

  • How you cut the squash: halved lengthwise, crosswise, or sliced in rings.
  • The cooking methods: oven-baked, steamed in a crock-pot, microwaved.

Here I am sharing the best method to bake spaghetti squash for the best spaghetti squash casserole.

It means that the flesh will be crunchy, firm, slightly caramelized, but not watery or mushy!

First, preheat the oven to 400°F (200°C), the fan-forced mode works faster, and it is preferable. Then, line a large baking tray with parchment paper and lightly oil the paper.

Low carb Spaghetti squash casserole

Cutting the squash

The best way to cut a spaghetti squash to bake it evenly is to cut it lengthwise.

First, trim the ends. Then, stand the squash up on one steam and cut to obtain two spaghetti squash boats.

Next, scoop out all the seeds and discard them.

Finally, place each spaghetti part with the flesh side down onto a baking sheet covered with a piece of parchment paper.

Make sure you brush the paper or the squash in contact with the paper with olive oil. Finally, bake for 30-40 minutes.

Keto Baked Alfredo Squash Casserole

Baking time

The baking time is the key. If you bake your squash too much, the spaghetti squash will not form firm noodles. It will be mushy and soft. So always check the baking process by:

  • Checking the color of its skin – when it starts to darken or brown, it is cooked!
  • Inserting a knife into the squash shell after 30 minutes. If the shell is soft and the knife goes through even a little bit, remove the tray from the oven, flip one squash boat and start grating the flesh with a fork.

If the strands are yellow/golden, slightly caramelized on the sides, and come out easily, it means it is cooked through.

How To Make The Vegetable Spaghetti

Flip over the two baked spaghetti squash boats and let the steam come out.

When the steam is out, wear a mitten and hold the squash with one hand, and with the other hand, pull apart the flesh using a fork.

It will form long, crunchy vegetable noodles, about 5 cups per spaghetti squash. Set aside on a baking dish and discard the squash shells.

Baked Spaghetti squash casserole

Keto Alfredo Sauce

This is a cheesy spaghetti squash casserole recipe using a creamy Alfredo garlic sauce.

To make the sauce, first, melt butter into a saucepan, then add heavy cream and shredded cheese – Parmesan is the best!

Stir constantly until the sauce is thick and forms strings of cheese.

Now add chopped parsley, salt, garlic, and an extra 1/2 cup of unsweetened almond milk to make a cheesy sauce, easy to pour over the baking dish.

Pour the sauce over the baking dish containing the baked squash spaghetti.

Use a spoon to combine the sauce into the vegetable noodles to cover all spaghetti evenly and create a creamy garlic spaghetti squash casserole.

If you want a different Alfredo Sauce, you can make my Cauliflower Alfredo Sauce.

How to bake Spaghetti squash alfredo ?

Meat Sauce: Chicken Alfredo Casserole

For the chicken Alfredo casserole lovers, you can adapt the recipe by adding 2 shredded chicken breasts into the casserole.

First, combine the cooked shredded chicken into the creamy sauce and pour it onto the baking dish containing the baked squash spaghetti.

Finally, stir to evenly cover the spaghetti with the sauce and top the casserole with shredded mozzarella.

Bake on medium-high heat at 350°F (180°C) for 15 minutes to broil the cheese on top.

Keto Baked Squash Casserole

Can I Make This Casserole Ahead?

Yes, you can make ahead your spaghetti squash casserole. There are two options to make this keto casserole recipe 24 hours to 48 hours before serving, depending on how you want to serve the dish.

  • Meal preparation for single serves – follow the entire recipe, store the whole casserole in the fridge, wrap the baking dish with plastic wrap. Then, rewarm by single-serves in the microwave, saucepan, or oven until piping hot.
  • Family gatherings – if you want to serve this vegetarian spaghetti squash casserole beautifully, I recommend assembling the casserole just before serving. It means that the day before, you pre-bake the squash spaghetti and Alfredo sauce and store them separately in the fridge, in 2 airtight containers. Then, assemble the casserole just before serving, bake following the recipe and serve.
Simple Spaghetti squash casserole

An Egg-Free Breakfast Casserole

We all sometimes love an egg-free keto breakfast, and this spaghetti squash breakfast casserole is perfect for it.

Your casserole will store for up to 3 days in the fridge or freeze in single-serve airtight containers.

Then, rewarm your portion in the microwave or saucepan, or hot oven just before serving.

Baked Spaghetti squash casserole

Leave me a comment below if you want to see more spaghetti squash recipes on the blog! And if you made this simple spaghetti squash casserole, don’t forget to share a comment or review below.

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Vegetarian Spaghetti squash casserole

Keto Spaghetti Squash Alfredo-Style

6.7gNet Carbs
This cheesy spaghetti squash casserole uses spaghetti squash as a low-carb pasta with a creamy Garlic Alfredo sauce.
Prep: 40 minutes
Cook: 20 minutes
Total: 1 hour
Yield: 9 servings (1/2 cup)
Serving Size: 1 serving
4.90 from 959 votes

Ingredients

  • 1 whole Spaghetti Squash baked, pulled apart into spaghetti – about 5 cups spaghetti

Keto alfredo sauce

  • ¼ cup Unsalted Butter
  • 1 cup Heavy Cream
  • ½ cup Unsweetened Almond Milk
  • 3 Garlic Cloves crushed or 1/2 teaspoon garlic powder
  • ¼ cup Fresh Parsley finely chopped
  • 1 teaspoon Salt
  • ½ teaspoon Pepper
  • 1 ½ cup Shredded Parmesan

Topping

For the chicken Alfredo option add

This recipe may contain Amazon or other affiliate links. As an Amazon Associate I earn from qualifying purchases.

Instructions

  • Preheat oven to 400°F (200°C).
  • Grease a 1.5-liter square glass or ceramic baking dish with butter or a rectangle 13-inch (33 cm) x 9-inch (22 cm) baking dish. Set aside.
  • Line a large baking tray with parchment paper. Set aside.

Preparing the spaghetti squash

  • Using a sharp knife, cut off the extremities of the spaghetti squash.
  • Stand the squash upright on the benchtop, placing a chopping board under it, and cut the squash lengthwise to divide it in half.
  • Use a tablespoon to scrape out all the spaghetti squash seeds and discard them.
  • Brush the cut-side of each squash with olive oil or spray oil all over.
  • Place each half squash, cut-side down, onto the prepared baking tray. Bake the squash for 30-40 minutes or until a knife inserted into the squash shell goes in and the inside of the squash is golden, and you can pull apart vegetable spaghetti from it. The smaller the squash is, the faster it is cooked. So I recommend checking the squash after 30 minutes. Open your oven, flip the squash on the other side, and using a fork, try to pull apart/fluff the spaghetti out of the squash. If it comes out easily, it is cooked. If not, flip back the squash on the tray, cut-side down, and keep baking for 10 minutes.
  • Remove from the oven, flip over the two squash using an oven mitten to avoid burning yourself. Let the steam evaporate for 10 minutes.
  • Then, keeping the oven mitten on, hold the squash with one hand and pull apart the spaghetti with a fork, scraping the flesh.
  • Place all the spaghetti noodles into the prepared baking dish. Spread evenly to cover the dish. Set aside while making the sauce.

Make the Alfredo Sauce

  • In a small saucepan, melt butter over low heat.
  • Stir in heavy cream, crushed garlic, salt, pepper, and shredded Parmesan cheese.
  • Stir and cook on low heat, simmering the sauce for 1-3 minutes until cheese is melted and the sauce thickens and strings of cheese form.
  • Stir in chopped parsley and unsweetened almond milk to make the sauce thinner and easy to pour over the baking dish. If you are using shredded chicken, add the shredded cooked chicken breast into the sauce now. Remove from heat.

Assemble the casserole

  • Pour the sauce all over the baking dish containing the baked spaghetti squash noodles and use a spoon to combine the sauce with the vegetable spaghetti. Stir well to make sure all the noodles are covered with the sauce.
  • Add shredded mozzarella all over the baking dish and bake at 350°F (180°C) for 15 minutes. Then, if cheese is not broiled yet, switch the oven to broil mode for 1-2 minutes to broil cheese on top.
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Serving Size: 1 serving
Yield: 9 servings (1/2 cup)
Serving: 1servingCalories: 326kcal (16%)Carbohydrates: 8.1g (3%)Fiber: 1.4g (6%)Net Carbs: 6.7gProtein: 19.8g (40%)Fat: 24.3g (37%)Saturated Fat: 14.2g (89%)Polyunsaturated Fat: 0.2gMonounsaturated Fat: 0.1gCholesterol: 102.5mg (34%)Sodium: 730.8mg (32%)Potassium: 316.5mg (9%)Sugar: 2.7g (3%)Vitamin A: 928.2IU (19%)Vitamin C: 3.2mg (4%)Calcium: 289.4mg (29%)Iron: 0.5mg (3%)
Carine Claudepierre

About The Author

Carine Claudepierre

Hi, I'm Carine, the food blogger, author, recipe developer, published author of a cookbook and many ebooks, and founder of Sweet As Honey.

I have an Accredited Certificate in Nutrition and Wellness obtained in 2014 from Well College Global (formerly Cadence Health). I'm passionate about sharing all my easy and tasty recipes that are both delicious and healthy. My expertise in the field comes from my background in chemistry and years of following a keto low-carb diet. But I'm also well versed in vegetarian and vegan cooking since my husband is vegan.

I now eat a more balanced diet where I alternate between keto and a Mediterranean Diet

Cooking and Baking is my true passion. In fact, I only share a small portion of my recipes on Sweet As Honey. Most of them are eaten by my husband and my two kids before I have time to take any pictures!

All my recipes are at least triple tested to make sure they work and I take pride in keeping them as accurate as possible.

Browse all my recipes with my Recipe Index.

I hope that you too find the recipes you love on Sweet As Honey!

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    79 Thoughts On Keto Spaghetti Squash Casserole with Alfredo Sauce
    1 2 3
  1. 5 stars
    I made this topped with gulf shrimp fried in butter and Old Bay Seasoning. It was amazing!
    Thank you for sharing this recipe!

  2. This recipe is AMAZING!! This will definitely be a “do again” recipe and often! Thanks for posting this recipe!!

  3. Hello, this looks yummy, I am not doing a keto diet, just looking for gluten-free. Two questions, have you tried making the spaghetti squash in a pressure cooker and what would you suggest to make this with less fat, maybe whole milk or half-and-half instead of heavy cream? Thanks.

  4. 5 stars
    I always come back to this recipe – so dependably delicious every time!!! Chills and freezes beautifully as well!
    We sometimes add imitation crab before baking (depends on your personal taste) and everyone loves it

  5. I’m making this tonight, it is in the oven as we speak & the kitchen smells heavenly! I tasted the sauce before pouring over the squash and it was garlic, cheesy yum mines! Can’t wait for it to be ready. I am serving it with some simple steamed broccoli.

  6. 5 stars
    This was so good! I had spaghetti squash from my garden for the recipe. I used a store bought Alfredo that was 0 carbs and added some chopped spinach instead of psrsley. I will definitely be making this agsin! Yum!!

    • 5 stars
      This was absolutely delicious and easy! I used Silk coconut whipping cream and subbed in 1/2 c 0% Fage Greek yogurt for the almond milk (didn’t have any). I also added to the spaghetti squash 3 c chopped, cooked broccoli and 8oz sliced baby Bella mushrooms. Will definitely be making again, especially since the family loved it as much as I did.

  7. This recipe is delicious! I didn’t have any chicken but I’m sure it would be great too! Good enough for Thanksgiving or Christmas dinner.

  8. 5 stars
    Loved the easy instructions and casserole. I took you recipe and added chopped green onion and red onion, mushrooms to the squash, and nutritional yeast(cheese flavor)to the sauce. Put. It all in a bowl mixed with the sauce. Was really a good keto recipe. Thank You

  9. 5 stars
    Freaking AMAZING!! I seriously have made this three times in the last month! It’s sooooo good!!

1 2 3

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