Spaghetti Squash Casserole

Last updated: May 18, 2023 · Recipes developed by Vered DeLeeuw and nutritionally reviewed by Rachel Benight MS, RD · This website generates income via ads and uses cookies.

Jump to Recipe Jump to Video Print Recipe

This cheesy spaghetti squash casserole makes a wonderful side dish. Made with squash, sour cream, and cheddar, it's substantial and filling enough to serve as a meatless main course.

The leftovers are very good too, and you can quickly reheat them in the microwave.

A slice of spaghetti squash casserole served on a white plate.

I love spaghetti squash. The first time I made 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!

I make many recipes using this versatile vegetable. I like to make spaghetti squash with meat sauce, spaghetti squash boats, spaghetti squash and meatballs, and simply baked spaghetti squash.

This spaghetti squash casserole is one of my favorite recipes. It's cheesy, delicious, and so easy to make!

I started out making it whenever I had leftover microwave spaghetti squash. But it is so good, so tasty and filling, that now I make it whenever I get the chance.

Jump to:

Ingredients
Variations
Instructions
Recipe FAQs
Serving Suggestions
Storing Leftovers
More Casserole Recipes
Recipe Card

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 by half, 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.

Variations

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 grilled chicken breast and turn this casserole into a complete meal.
Iike to add bacon bits to the mixture.
You can use different cheeses. Provolone works well, and so does Gouda.
Use softened cream cheese instead of sour cream.
You can use dried oregano instead of thyme. Both work equally well.

Like all casserole recipes, this one is flexible and forgiving. So go ahead and experiment with your own additions!

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. (Photo 1).
Now, scoop out the pulp and seeds, and rake a fork back and forth to remove strands of the flesh into a bowl. (Photo 2).
Whisk together an egg, sour cream, and a few spices. Add the squash strands and some shredded cheese and mix until uniform. (Photo 3).
Transfer the mixture to a greased baking dish and bake it until browned, about 40 minutes at 400°F. (Photo 4).
Let the casserole rest, then cut it into four squares, and serve. (Photos 5-6).

A six-photo collage showing the steps for making a spaghetti squash casserole.

Recipe FAQs

Should I add flour to this casserole?

There's 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.

Can I freeze this casserole?

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.

Should I cook the spaghetti squash before adding it to the casserole?

Yes. You can either bake it in the oven or microwave it. I prefer microwaving because it's easier and faster.

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: