Vegetarian Spaghetti Squash Casserole

cheesy baked spaghetti squash noodles on a blue plate with a silver fork

Vegetarian Spaghetti Squash Casserole

This cheesy baked spaghetti squash casserole is a veggie-packed meal or side dish you’re going to fall in love with! Tender spaghetti squash and mixed veggies. are layered with homemade tomato sauce, mozzarella, and Parmesan, then baked until hot and bubbly. It’s an easy way to turn spaghetti squash into a satisfying vegetarian dinner.

Course Main Course

Cuisine American

Diet Gluten Free, Vegetarian

Keyword Spaghetti Squash Casserole

Prep Time 30

Cook Time 45

Total Time 1 15

Servings

Calories 248kcal

Author Katie Trant

Ingredients

1 large spaghetti squash about 3lbs / 1400g
2 Tablespoons extra virgin olive oil
1 large yellow onion diced
2 cloves garlic crushed
1 large stalk celery finely diced
2 medium carrots finely diced
½ cup dry white wine or white vermouth
14 ounce can crushed tomatoes
salt and pepper
8 ounce mozzarella shredded
½ cup finely grated Parmesan cheese

US Customary - Metric

Instructions

COOK THE SPAGHETTI SQUASH

Pierce your spaghetti squash several times with the tip of a sharp knife.
1 large spaghetti squash
Place the spaghetti squash on a microwave-proof plate, and microwave on high for 12 minutes, stopping to check on and rotate the squash every three minutes.
Remove the squash from the microwave and let it cool until you're able to handle it comfortably.
Slice the squash in half, and use a spoon to remove the seeds.
Use a fork to shred the spaghetti squash flesh into "noodles" and transfer the noodles into a bowl.

MAKE THE SAUCE

Preheat your oven to 350°F / 180°C at this point.
Heat the olive oil over medium heat in a large heavy-bottomed skillet.
2 Tablespoons extra virgin olive oil
Add the onion, and cook, stirring often, until it is well-browned - about 10-15 minutes.
1 large yellow onion
Add the garlic, celery, and carrots, and cook for about 5 minutes more, until the vegetables are softened.
2 cloves garlic, 1 large stalk celery, 2 medium carrots
Add the white wine and stir the contents of the pan well to lift the flavour from the bottom. Allow the wine to evaporate almost entirely.
½ cup dry white wine
Add the crushed tomatoes, and stir to combine well. Season with salt and pepper.
14 ounce can crushed tomatoes , salt and pepper

ASSEMBLE THE CASSEROLE

Add the tomato sauce to the spaghetti squash noodles, and stir to combine well.
Transfer to a 9x9 inch casserole dish.
Place in the oven, and bake for 30 minutes. The sauce should be bubbling up around the sides at this point.
Remove the casserole dish from the oven and scatter the cheeses over the top.
8 ounce mozzarella, ½ cup finely grated Parmesan cheese
Return to the oven and bake for an additional 15 minutes, until the cheese is browned and bubbly on top.
Remove from the oven and let rest for 5 minutes before serving.

Notes

Nutrition values are an estimate only.
You're aiming for teeny tiny finely diced vegetables in this dish. Feel free to shred them or do the chopping in your food processor to save time.
While this recipe calls for white wine, I seldom have white wine kicking around in the colder months, but I always have a bottle of white vermouth in the liquor cabinet and use them interchangeably for cooking.
Can I make this recipe in advance? You sure can! You can prepare everything in advance and leave it in the refrigerator until you're ready to bake it.
Tip! Cook the spaghetti squash ahead of time and this recipe will come together quickly.
Can I freeze this recipe? To be honest, I don't love this recipe frozen and re-heated. I recommend you keep the leftovers in the fridge and eat them up within 3-4 days.

Nutrition