This post may contain affiliate links. Please see my disclosure policy.

This Vegetarian Spaghetti Squash Casserole is packed with vegetables and protein. Spaghetti squash is cooked and mixed with a tasty homemade tempeh bolognese, then topped with freshly grated parmesan and oven-baked for a healthy and delicious weeknight dinner. It’s perfect for meal prep, too!

baked spaghetti squash casserole with tempeh bolognese in white baking dish

The other week on Instagram I asked you guys what types of recipes you wanted to see for fall, and there were a bunch of requests for casserole dishes. I’ll be honest – casseroles aren’t something I make very often, but I was up for the challenge!

I can now see why so many people are fans of the dish – they’re super warming and cozy, not to mention you can pack SO many tasty and nutritious ingredients in there.

So with that said, I’m excited to share this recipe for a Vegetarian Spaghetti Squash Casserole today. This is a great option for a family dinner, but also for meal prep!

This casserole is PACKED with veggies and fibre from the spaghetti squash, marina sauce, bell peppers, and carrots.

There’s also TONS of plant-based protein in this dish, as the squash is mixed with a homemade “tempeh bolognese.” For flavour, we’re using all the dried herbs and some freshly grated parmesan to top everything off.

Curious to learn more? Let’s get cooking! And don’t worry – I show you exactly how to cut and cook spaghetti squash too, in case you’re new to that! Promise it’s not too difficult 🙂

baked spaghetti squash casserole with tempeh bolognese in white baking dish

Is Spaghetti Squash Healthy?

Spaghetti squash is a delicious winter squash that comes out in spaghetti-like strands. While it doesn’t exactly compare to pasta, I still love it for its taste and impressive nutrition profile!

Some of spaghetti squash’s health benefits:

  • high in certain micronutrients like vitamin C, B6, manganese, niacin, and potassium
  • rich in antioxidants (like beta-carotene and vitamin C), which helps to fight free radical damage to your body’s cells
  • a GREAT source of dietary fibre, with a one-cup serving providing 9% of your daily needs (2.2 grams)
    • Fibre plays an important role in promoting digestive health, lowering cholesterol, balancing blood sugar, and helping us feel satiated!
spaghetti squash sliced in half on wooden cutting board

How To Cut & Cook Spaghetti Squash

If you’re curious to give spaghetti squash a try, but you’re not sure how to prepare it – you’re in luck! It’s actually super easy, and the hardest part is CUTTING through the squash itself.

Start by preheating your oven to 375F and lining a large baking sheet.

With a sharp chef’s knife, I like to cut off the ENDS of the squash first, so that you can stand it upright. Then, cut down through the squash lengthwise until it separates into two halves. I find it helpful to use a dish towel to help push the sharp end of the knife down.

Next, remove the seeds from the squash. Drizzle and brush the insides of the squash with olive oil, and generously crack salt and pepper over top.

Flip the squash FACE SIDE DOWN onto the baking sheet, and place in the oven for about 40 minutes, depending on the size of the squash.

Once the squash is cooked and tender, remove from the oven. Flip the squash over and let cool for a few minutes. With a regular kitchen fork, scrape the flesh out of the squash into spaghetti-like strands (see picture below).

At this point, your spaghetti squash is ready and you can simply add sauce and go. If you want to make this casserole though, keep reading!

close up of cooked spaghetti squash

How To Make Tempeh Bolognese

While the spaghetti squash is baking in the oven, you can prepare the tempeh bolognese.

Crumbling tempeh makes a great plant-based alternative to ground meat, as its protein content is quite comparable (100 grams of tempeh has 19-21g of complete protein, depending on the brand)!

To make the tempeh bolognese, start by chopping carrots and bell peppers into small pieces and mincing garlic. Then, crumble the tempeh with your hands until it starts to resemble ground meat (it’s ok if the pieces are slightly bigger and uneven).

In a large skillet, add olive oil and minced garlic.

Then, add the crumbled tempeh along with tamari (or soy sauce) and cook for about 5-7 minutes, or until the tempeh starts to brown.

Once it’s browned, add the chopped vegetables and continue to cook.

Then, add the marina sauce, tomato paste, and dried herbs (thyme, oregano, and basil), cooking for another 5 or so minutes.

tempeh bolognese in a skillet

How To Prepare The Casserole

To make the casserole, simply add the spaghetti squash strands and tempeh bolognese to a large casserole dish. Stir everything together well, so that the sauce is evenly distributed among the squash. Taste and adjust seasonings as needed.

Sprinkle freshly grated parmigiano reggiano overtop of the entire dish (or other grated cheese of choice) and place the casserole in the oven for about 12 minutes, or until the cheese has melted. Finish with freshly cracked pepper and fresh herbs as desired!

How To Store & Reheat

Leftovers can be stored in airtight containers for a meal prep/make ahead option. They’ll keep for about 3-5 days and can easily be reheated in the microwave.

Vegan Alternative

This dish is naturally gluten-free and can also be made dairy-free/vegan by omitting the parmesan cheese.

If you’d like, you can try to top it with a vegan cheese alternative or you could sprinkle some nutritional yeast overtop instead. The nutritional yeast won’t melt like the parmesan, but it will still add that cheesy flavour!

baked spaghetti squash casserole with tempeh bolognese in bowl

More Easy Vegetarian Meal Ideas

Did you give this Vegetarian Spaghetti Squash Casserole a try? Let me know by leaving a comment and recipe rating below!

If you do make this recipe, don’t forget to tag me on Instagram or Pinterest – seeing your creations always makes my day. You can also subscribe to my email list to never miss a new recipe or nutrition education post!

Get the Recipe: Vegetarian Spaghetti Squash Casserole

This Vegetarian Spaghetti Squash Casserole is packed with vegetables and protein. Spaghetti squash is cooked and mixed with a tasty homemade tempeh bolognese, then topped with freshly grated parmesan and oven-baked for a delicious weeknight dinner. Vegan/dairy-free option available.
baked spaghetti squash casserole with tempeh bolognese in white baking dish
Print Pin
4.48 from 19 votes
Leave a Review

Ingredients

Spaghetti Squash:

  • 1 large spaghetti squash
  • Approx. 1 Tbsp extra virgin olive oil (to brush squash)
  • Salt + pepper (to crack over squash)

Tempeh Bolognese:

Toppings:

  • 1.5-2 cups freshly grated parmigiano reggiano (or other meltable cheese/vegan cheese if desired)
  • Freshly chopped basil (optional)

Instructions

  • Preheat oven to 375F and line a large baking sheet.
  • Cook spaghetti squash. With a sharp chef's knife, cut ends of squash and stand upright. Cut down through the squash lengthwise, until it separates into two halves. Remove the seeds, and brush insides with olive oil. Crack salt + pepper generously. Place squash face side down on baking sheet, and cook in the oven for about 40 minutes.
  • While the squash cooks, prepare the other ingredients. Mince garlic, and chop carrots and bell peppers into small pieces. Crumble tempeh with hands until it resembles ground meat.
  • Make the tempeh bolognese. In a large skillet, add olive oil and minced garlic. Cook for 1-2 minutes, until garlic browns. Add crumbled tempeh and toss with tamari, cooking for 5-7 minutes until the tempeh starts to brown. Once browned, add the chopped vegetables, and cook for another 5-7 minutes until the veggies start to soften. Finally, add marina sauce, tomato paste, thyme, oregano, and dried basil. Cook altogether for a few minutes and set aside.
  • Once squash has cooked, remove from oven. Flip over and let cool for a few minutes. With a fork, scrape the flesh out of the squash into spaghetti-like strands.
  • Add the strands of spaghetti squash to a large casserole dish along with tempeh bolognese. Stir everything together well, so that the sauce is evenly distributed among the squash. Taste and adjust seasonings as needed.
  • Sprinkle freshly grated cheese overtop of the entire dish and place in the oven for another 12 minutes, or until the cheese has melted.
  • Remove casserole from oven, and serve with freshly cracked pepper and fresh herbs as desired. Enjoy hot!

Notes

*While best enjoyed fresh from the oven, leftovers can be kept for about 3-5 days in an airtight container in the fridge. They can be easily reheated in the microwave, making this dish a great meal prep option!
*For a vegan/dairy-free dish, simply omit the cheese. Feel free to use a shredded vegan cheese as an alternative, or sprinkle with nutritional yeast for a cheesy flavour!

Did you make this recipe?

Let me know by leaving a recipe rating below, or by tagging @walderwellness on Instagram. I love seeing your beautiful creations!

Pin it for later:

Pinterest graphic for vegetarian spaghetti squash casserole recipe.
This post may contain affiliate links. Please see my disclosure policy.