Deliciously cheesy spaghetti squash casserole makes a wonderful side dish. Made with squash, sour cream, and cheddar, it's actually substantial and filling enough to serve as a meatless main course.
Leftovers are very good too, and you can quickly reheat them in the microwave.
I love spaghetti squash. The first time I microwaved it, then raked a fork back and forth and saw the beautiful pasta-like strands, I was hooked. It's delicious, affordable, and fun to eat!
This spaghetti squash casserole is one of my favorite recipes to make with this tasty root vegetable. It's cheesy, delicious, and so easy to make! I started out making it whenever I had leftover cooked spaghetti squash. But it is so good, so tasty and filling, that now I make it whenever I get the chance.
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Ingredients
You'll only need a few simple ingredients to make this tasty casserole. The exact measurements are included in the recipe card below. Here's an overview of what you'll need:
Spaghetti squash: I use a fairly large 3-lb. squash in this recipe.
Egg: I use large eggs in most of my recipes, this one included.
Sour cream: I tried once to use Greek yogurt instead and was underwhelmed. I think sour cream is better.
Minced garlic: Mince it yourself, or use the stuff that comes in a jar. Both work. Garlic powder (1 teaspoon) works too.
Kosher salt and black pepper: If using fine salt, you should reduce the amount you use, or the dish could end up too salty.
Dried thyme: Make sure it's fresh! A stale spice can easily ruin a dish.
Shredded sharp cheddar: Another cheese that works great in this casserole is Gruyere.
Instructions
Making this spaghetti squash casserole is truly easy. Scroll down to the recipe card for detailed instructions. Here are the basic steps:
Your first step is to cook the squash. I cook it in the microwave. You can also bake it in the oven.
Now, scoop out the pulp and seeds, and rake a fork back and forth to remove strands of the flesh into a bowl.
Whisk together an egg, sour cream, and a few spices. Add the squash strands and some shredded cheese and mix until uniform.
Transfer the mixture to a greased baking dish and bake it until browned, about 40 minutes at 400°F.
Frequently asked questions
There's actually no need to add flour. The egg acts as a binder and the sour cream adds substance and creaminess. The casserole's texture is excellent without any added starch.
Yes. Allow it to cool completely, then wrap it in a layer of plastic wrap and then a layer of foil. It can be frozen for up to three months.
Yes. You can either bake it in the oven or microwave it. I prefer microwaving because it's easier and faster.
Variations and substitutions
I love this recipe as is and almost always make it as written. But in case you'd like to vary the basic recipe, here are a few ideas for you:
- Add more veggies, such as a handful of cooked and drained spinach, a handful of sauteed mushrooms, or ¼ cup of green onions.
- Add cooked shredded chicken.
- Add bacon bits.
- You can use different cheeses. Provolone works well.
- Use softened cream cheese instead of sour cream.
- You can use dried oregano instead of thyme.
Like all casserole recipes, this one is flexible and forgiving. So go ahead and experiment with your own additions.
Serving suggestions
This tasty casserole makes a wonderful side dish, but is also substantial and filling enough to serve as a meatless main dish.
I do usually serve it as a side dish. And since I bake it in a 400°F oven, I like to serve it with a main dish that I can cook in the same oven, such as pork meatballs or baked chicken thighs.
Storing leftovers
Leftovers keep well in the fridge, in a sealed container, for up to 4 days. Reheat them gently, in the microwave on 50% power.
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Recipe card
Cheesy Spaghetti Squash Casserole
INGREDIENTS
- Olive oil cooking spray
- 1 3 lb. raw spaghetti squash or 2 ½ cups (450 grams) cooked spaghetti squash
- 1 large egg
- ½ cup sour cream
- 1 teaspoon Diamond Crystal kosher salt
- ¼ teaspoon black pepper
- ½ teaspoon dried thyme
- 1 tablespoon minced fresh garlic
- 1 cup shredded sharp cheddar cheese
INSTRUCTIONS
- Preheat oven to 400 degrees F. Lightly spray a 1.5-quart baking dish with olive oil cooking spray.
- If you need to cook the spaghetti squash: Pierce the spaghetti squash in a few spots with a sharp knife. Microwave 6 minutes; turn to the other side and microwave 6 more minutes, until soft to the touch. Let stand for 5 minutes to finish cooking. Using a sharp knife, cut the spaghetti squash in half lengthwise. Allow to cool 5 minutes, until easier to handle. Scoop out the pulp and seeds from the center, then rake a fork back and forth to remove strands of the flesh onto a bowl. Set aside.
- In a large bowl, lightly whisk the egg. Add the sour cream, kosher salt, black pepper, dried thyme, and minced garlic. Whisk until smooth.
- Mix in the cooked spaghetti squash and the shredded cheese.
- Transfer the mixture to the prepared baking dish. Bake until browned, about 40 minutes (it will smell wonderful!).
- Allow the casserole to cool for 10 minutes, then scoop it onto plates. Or if you're patient, carefully cut it into squares and serve.
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NOTES
- Add more veggies, such as a handful of cooked and drained spinach, a handful of sauteed mushrooms, or ¼ cup of green onions.
- Add cooked shredded chicken.
- Add bacon bits.
- You can use different cheeses. Provolone works well.
- Use softened cream cheese instead of sour cream.
- You can use dried oregano instead of thyme.
ADD YOUR OWN NOTES
NUTRITION PER SERVING
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Vered DeLeeuw, LL.M., CNC, has been following a low-carb real-food diet and blogging about it since 2011. She's a Certified Nutrition Coach (NASM-CNC), has taken courses at the Harvard School of Public Health, and has earned a Nutrition and Healthy Living Certificate from Cornell University. Her work has appeared in several major media outlets, including Healthline, HuffPost, Today, Women's Health, Shape, and Country Living. 