Spaghetti Squash Casserole

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My easy spaghetti squash casserole, packed with nutritious vegetables of zucchini, bell peppers, and carrots in a delicious tomato-based sauce poured over spaghetti squash and baked in the oven, is our new family favorite comforting meal. It’s gluten-free, vegan, and ready in just under an hour.

When I think of comfort food, pasta bakes or casseroles top the list. Since they aren’t always healthy, I now make lighter versions using spaghetti squash, like this curry spaghetti squash with chickpeas, for a lower-calorie meal.

My kids have been huge fans of spaghetti squash ever since they tried my vegan spaghetti squash soup, so every time I want a comforting casserole or pasta dish, I just bake squash and make spaghetti-like strands with it. This spaghetti squash casserole combines Italian flavors with a super cheesy topping that is totally family-friendly and yummy. You’re gonna love it!

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🥘 Ingredients

My vegetarian spaghetti squash casserole bake requires simple ingredients that you most probably have at home or can easily find at the grocery store.

Spaghetti Squash: The star of this recipe, spaghetti squash, is the best alternative to pasta when I want something light and nutritious.

Olive Oil: I only use a drizzle of olive oil in this recipe to saute the vegetables.

Vegetables: I use a host of healthy vegetables in this healthy casserole recipe, like diced yellow bell peppers, chopped onion, diced carrots, zucchini, and garlic.

Italian Seasoning and Oregano: Any classic Italian spices will do, but my favorites are a pre-mixed Italian seasoning and dried oregano.

Crushed Red Pepper: I add a subtle spice to this healthy spaghetti squash main dish recipe with crushed red pepper flakes!

Seasoning: Every dish tastes better with a sprinkle of salt and pepper. I add a bit with the veggies, and then at the end to taste before pouring cheese over.

Pasta Sauce: Use whatever sauce you prefer for this spaghetti squash pizza casserole. My favorite brands are Muir Glen or Cucina Antica because they are low in sugar.

Shredded Cheese: I recommend using an Italian blend of shredded cheese or shredded parmesan for this spaghetti squash cheese casserole to keep that authentic Italian flavor.

Substitutions

Calabrian Chile Peppers: Another fun idea I like is to use calabrian peppers instead of crushed red!

Garlic Powder: When I don’t have fresh garlic for any of my recipes, I substitute it with garlic powder instead. Use half the amount of fresh garlic.

Parsley: I use parsley or other Italian spices in this healthy spaghetti squash recipe when I don’t have any oregano.

Meat Sauce: If you aren’t vegetarian or vegan, feel free to substitute your sauce for a meat option.

Mozzarella Cheese: If you don’t have an Italian blend of cheese or parmesan handy, mozzarella on its own would be great, or for a vegan cheese, you can buy a dairy-free cheese brand or make my vegan parmesan cheese.

🔪 How To Make

The hardest part about this dish is simply resisting the urge to eat the whole thing! Here is how I make this creamy spaghetti squash casserole:

Preheat and Cook Squash: First, I preheat the oven to 350ºF. Then, poke the spaghetti squash all over with a knife, and cook it in the microwave on a microwave-safe plate for 8 to 12 minutes until soft. If you don’t have a microwave, place the poked squash on a baking sheet and bake at 375ºF for 45 to 60 minutes.

Saute Veggies: While the squash is cooking, I add oil, yellow pepper, red onion, carrots, zucchini, garlic, Italian seasoning, dried oregano, crushed red pepper, and salt and pepper to a large pan, cooking over medium heat for about 10-15 minutes until fully cooked through.

Prepare The Squash: Once the squash is soft and tender, I cut the squash in half with a sharp knife, scoop out the seeds of each of the squash halves, and with a fork, scrape the flesh from the peel. It should flake off easily into spaghetti-like strands.

Mix Ingredients: Next, I place the spaghetti strands in a casserole dish and add the cooked veggies, pasta sauce, and half of the cheese, mixing well to combine.

Bake: Finally, I sprinkle the other half of the cheese on top of the casserole and bake it in the preheated oven for 30 minutes until the cheese is bubbly and browned.

Let Cool: Allow to cool for five minutes before serving, and enjoy!

📖 Variations

This delicious spaghetti squash casserole is great as it is, but I have made other variations of this classic low-calorie dish. Here are some of my favorites.

Enchilada version: I give it a Mexican twist by transforming it into an enchilada casserole. I substitute marinara sauce for enchilada sauce, parmesan cheese for cheddar cheese, and add 1 cup of black beans and 1 tablespoon of taco seasoning to the vegetables. I serve with vegan sour cream, tortilla chips, and sliced jalapenos.

Gluten-Free With Meat: For those that are not vegan or vegetarian, you can mix in 1 pound of cooked ground beef, ground turkey, or chopped chicken breast to the veggie mix and mix in the sauce for a meaty spaghetti squash casserole version..

Different Sauces: Try this gluten free spaghetti squash recipe with some of my homemade sauces to give it different flavors. Some of the best sauces are vegan bolognese, alfredo sauce without heavy cream, vodka sauce, or pesto without pine nuts.

🍽 Serving Suggestions

This casserole stands on its own, but I personally love pairing it with some crusty bread and salad as a side dish. Here are a few more of my favorite serving suggestions:

Salads: With casseroles, I usually opt for something light to aid the flavors of comforting casseroles like this with a spinach and arugula salad to boost the protein and fiber content, or a tomato avocado cucumber salad to complement the Mediterranean flavors of the veggie casserole.

Side dishes: If you’re like me and love to dip warm, crusty bread into your soup and stews, then this simple air fryer garlic bread recipe is just what you need to scoop that yummy casserole onto crusty, garlicky bread. Another favorite with my kids is these air fryer pizza rolls that go hand in hand with the tomato based flavors and cheesy goodness!

🧊 Storage Directions

Refrigeration: After the leftover spaghetti squash casserole has cooled to room temperature, I cover it tightly with plastic wrap or foil and enjoy it as leftovers the next day. It will keep for about 2-3 days.

Freezing: I freeze this healthy squash casserole recipe for 2-3 months by transferring the leftovers to an airtight container. Thaw in the fridge overnight before reheating and enjoying.

Reheating: When I want to reheat leftovers, I preheat the oven to 350°F, and bake the leftovers for around 15 minutes till hot or pour the contents into a microwave bowl and heat at 1-minute intervals till bubbling.

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