Creamy and comforting, this Spaghetti Squash Casserole makes a perfect keto side dish. Easy and cheesy, with tons of flavor, it turns your dinner into a hearty meal.
I had an absolute bumper crop of spaghetti squash from my garden this year. We grew a variety called stripetti with pretty green stripes, and we weren’t expecting that much out of it. It far exceeded our expectations.
And now we have so many, we need to find ways to use it up. So I am dreaming up as many spaghetti squash recipes as I can! And this creamy, cheesy Spaghetti Squash Casserole is one such recipe.
Oh boy, is it ever good. So hearty and flavorful, this might be my new go-to side dish for fall. At least until I work through all those squash. And with only 5.6g net carbs per serving, it fits the keto diet perfectly.
I may have eaten the leftovers for breakfast too. It goes perfectly with a fried egg and a few slices of bacon. Just saying!
Make sure to try my Twice Baked Spaghetti Squash too. It’s another of my favorites!
Ingredients you need
- Spaghetti squash: You will need a medium-size spaghetti squash for this recipe, which should be about 3 pounds in weight when whole. It will yield about 4 cups cooked squash.
- Sour cream: Sour cream gives the casserole a thick and creamy consistency.
- Garlic: I recommend using fresh garlic for the best flavor. You can use pre-minced, jarred garlic instead. If all you have is garlic powder, try using 1 teaspoon.
- Italian seasoning: This dried seasoning blend pairs perfectly with the squash and cheese.
- Shredded cheese: I used a mild cheddar for the filling and mozzarella for the top of the casserole, plus some Parmesan to play up the Italian flavor. But you can use other cheese as well. Fontina or gruyere would be lovely.
- Eggs: The eggs help bind the stringy squash together and give it a more coherent consistency.
- Basil: Fresh basil adds both color and flavor.
- Kitchen staples: Butter, salt, pepper, red pepper flakes
Step by step directions
1. Pre-cook the squash: Cut the spaghetti squash in half, crosswise, and scoop out the seeds. Place cut-side down on the prepared baking sheet and bake at 375ºF for 45 to 60 minute, or until the squash can be squeezed.
2. Scoop out the flesh: Remove and let cool for a few minutes, then scoop the flesh of the squash into a large bowl. Add the butter and let melt.
3. Mix the filling: Add the sour cream, garlic, Italian seasoning, salt, pepper, and red pepper flakes, and stir to combine. Then stir in the eggs, cheddar, and half of the Parmesan until well combined.
4. Sprinkle with cheese and bake: Spread in the prepared baking pan and top with the mozzarella and the remaining Parmesan. Bake at 350ºF for 30 to 35 minutes, until bubbly and browned.
Expert tips
I like to use a large heavy duty spoon for scooping out the seeds of the spaghetti squash. The flesh is quite tough when raw, so a flimsy spoon can easily bend under the pressure.
If your squash is larger than 3 pounds and yields more than 4 cups of cooked flesh, just save the rest for another use. You can refrigerate it for 4 or 5 days, or freeze it for up to 2 months.
Make it a meal!
Turn this spaghetti squash casserole from a side dish into a full meal. Try adding some cooked Italian sausage, ground beef, or cubed chicken to the filling. Then top with cheese and bake as directed.
Frequently Asked Questions
Spaghetti squash is a good option for keto and low carb diets, but some moderation is required. 1 cup of cooked spaghetti squash has 10g of carbs and 2.2g of fiber, so it’s a little higher in carbs than summer squash like zucchini. So it’s good to be mindful of how much you consume in one sitting.
The rind of spaghetti squash is very tough and hard to cut through. Make sure you use a very large, sharp knife and cut on a stable surface. Once you get through the first part of the rind, you will find it easier to cut through the rest. Cutting the squash in half crosswise is also easier than cutting lengthwise, as it’s a shorter distance.
This creamy spaghetti squash casserole has only 6.7g of carbs per serving and 1.1g of fiber. That amounts to 5.6g net carbs per serving.
Make Ahead and Storage Tips
If you want to get a jump on meal prep, this Spaghetti Squash Casserole is an ideal make-ahead side dish. You can roast the squash several days in advance, and just keep it in the fridge until you’re ready to assemble.
Or you can bake the full casserole and store it in the fridge for up 5 days, or the the freezer for up to two months. Make sure to wrap it up tightly to avoid freezer burn. Let it come to room temperature before warming it through in the oven.
More side dishes you might like
Spaghetti Squash Casserole Recipe
Ingredients
- 1 medium spaghetti squash, about 3 pounds
- 2 tbsp butter
- 1/2 cup (115 g) sour cream
- 4 cloves garlic, minced
- 1 tsp Italian seasoning
- 3/4 teaspoon (0.75 teaspoon) salt
- 1/2 tsp (0.5 tsp) pepper
- 1/4 tsp (0.25 tsp) red pepper flakes
- 4 ounces (113.4 g) white cheddar, grated
- 2 large eggs
- 1 ounce (28.35 g) freshly grated Parmesan, divided
- 2 tbsp chopped fresh basil
- 4 ounces (113.4 g) mozzarella, grated
Instructions
- Preheat the oven to 375ºF and line a baking sheet with parchment paper.
- Cut the spaghetti squash in half, crosswise, and scoop out the seeds. Place cut-side down on the prepared baking sheet and bake 45 to 60 minute, or until the squash can be squeezed.
- Remove and let cool for a few minutes, then scoop the flesh of the squash into a large bowl. Add the butter and let melt.
- Reduce the oven temperature to 350ºF. Lightly grease a 2 quart casserole dish.
- Add the sour cream, garlic, Italian seasoning, salt, pepper, and red pepper flakes, and stir to combine. Then stir in the eggs, cheddar, and half of the Parmesan until well combined.
- Spread in the prepared baking pan and top with the mozzarella and the remaining Parmesan. Bake 30 to 35 minutes, until bubbly and browned.
- Let cool a few minutes before serving. Sprinkle with additional chopped basil, if desired.
Notes
Storage Instructions:
Store the casserole in the fridge for up 5 days, or the the freezer for up to two months. Make sure to wrap it up tightly to avoid freezer burn. Let it come to room temperature before warming it through in the oven.Nutrition
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This was so amazing! I usually avoid spaghetti squash because it takes so long to bake vs the end result of most dishes, but I could eat this for breakfast. Thank you so much for the recipe!
This is FANTASTIC! Best flavor squash casserole I’ve ever made and I’ve made a lot. I didn’t have white cheddar so substituted fontina, but used as directed on the parm and mozzarella. I also left out the basil. Make sure to hide any leftovers so you can eat it all yourself!
This is a great recipe for a whole spaghetti squash taken out of the oven a bit too soon, which I did yesterday. The recipe is clear. Put the squash in a bowl, and add everything else. Easy peasy. Delish.
Recipe is delicious and my entire family enjoyed it. One tiny issue – the recipe directions do not say when to add the 2 T. of chopped basil.
My son said it tasted like Garlic bread and ate two servings! I call this winning! YUM!
Still not seeing when to add the spaghetti squash.
Step #3.
I am not seeing in the recipe when you add the spaghetti squash. Also, I already have my spaghetti squash prepared and in a freezer. Would you know how many cups I would need? Thank you.
Step 3 says: Remove and let cool for a few minutes, then scoop the flesh of the squash into a large bowl. Add the butter and let melt.
I’d say it’s about 4 cups.
Thanks for the amount. What I don’t see when the spaghetti squash is added? Or is it combined with everything? Thanks
Again…. Step 3. Pretty clear, it says to scoop out the flesh of the squash into the bowl.
I assume you mix it all together then put it in the baking dish?
Yes, all in the bowl, then into the dish.
Great recipe except the recipe card says bake for 10 minutes instead of the proper “30-35 mins “
I am not sure what you are looking at or where you are seeing that, but the recipe card clearly states 30 to 35 minutes and does not say 10 minutes anywhere. I think you might be mixing it up with this recipe: https://alldayidreamaboutfood.com/twice-baked-spaghetti-squash/
They are two different recipes entirely.
made this last night in my toaster oven. Smelled so good, I literally stood at the counter eating it out of the pan. so good!
DELISH! Made for a weeknight vegetarian meal, husband raved. Brought some to work for a single friend, too. This would be a really nice side for a holiday meal as well.
We make this in my house now instead of mashed potatoes! Never been keen on Spaghetti Squash, but let me tell you, THIS is the recipe to go with! Soooo flavorful and savoury.
Yay!!!
This was incredible! I can’t stop eating it!! I used different cheeses based on what I had, but otherwise followed the recipe as written. I will absolutely make it again!
I had leftover spaghetti squash that I used for this – it was delicious. I did add some browned onions to it 😀
can you use Greek yogurt in place of the sour cream?
I am not sure it will be as thick and rich, but you’re certainly welcome to try!
We love spaghetti squash in any form and this recipe is over the top great! Thank you for sharing it. Tiny hack we discovered for easy seed removal: use a butter curler to remove the seeds. Also works great to remove cantaloupe seeds.
Absolutely loved this,my husband can’t get enough 🥰
If I want to freeze half, do I freeze it before or after it’s been baked?
After.
This was the best recipe for spaghetti squash I have ever made. I only had grated parmesan and dry basil as well as I used marble cheese on top but was absolutely an excellent side casserole. You have got to try this one.
This is so tasty! I made it as a side but next time I think I’ll just add some diced chicken. The flavor lingers on your tongue making you eager for the next bite. Definitely a staple recipe in our house!
I’ve made a similar dish using spaghetti squash. My recipe is similar but I leave out the Italian seasonings, basil, Mozzarella and Parmesan cheese. I add a packet of Taco seasoning and cheddar cheese or a Mexican blend shredded cheese along with the sour cream and the other ingredients. If you like cilantro you can add that in place of the basil. Yummy