Creamy, cheesy vegan baked spaghetti squash casserole with mushrooms is the healthy comfort food recipe you’ve been looking for.
How to Cut and Cook Spaghetti Squash
We love squash season as much as the next home cook. But there’s no denying that bulky winter squashes like butternut, acorn and spaghetti can be daunting to cook with.
Size is one thing, and their wobbly bottoms surely don’t help when it comes to cutting. And then sometimes you just end up getting a squash with an especially tough skin.
There are a few easy at-home tricks to cutting and cooking spaghetti squash. It’s best to cut the squash in half before putting it in the oven. It cooks much faster and can steam from the inside out.
When you put it on a baking sheet, be sure to place it cut-side down. Otherwise, the squash tends to dry out. Also, I strongly recommend lining your sheet pan with parchment paper for any squash roasting activities. They tend to release a lot of liquid that hardens pretty quickly in the oven.
If you end up with one of those especially stubborn squashes, however, fear not. Don’t dull your knife and risk an injury by wrestling a tough-skinned gourd on the counter. Instead, stick the whole squash in the hot oven for 10 minutes or so to to soften up a bit.
Or, you can enlist Chef Mike.
As in microwave 🙂
Microwaving is the fastest way to go from whole, raw spaghetti squash to fully cooked strands. Here’s how to do it:
- Fill a shallow baking dish or even a wide bowl with about an inch of water.
- Place the spaghetti squash inside the dish, and microwave for 5 minute increments.
- Just like in the oven, the squash is ready when you can easily pierce it with a fork or knife.
You can always do a combo by starting in the microwave to soften the skin, then finishing in the oven.
Cheesy Vegan Sauce for Spaghetti Squash Casserole
The secret to this comforting, baked spaghetti squash casserole is cheesy, gooey sauce. We make ours 100% dairy free and gluten free with a few key ingredients.
- Non-dairy milk. We opt for cashew milk because it has a mild flavor. However, coconut, almond or oat milk would also work. Be sure to choose a dairy free milk that’s not flavored or sweetened though.
- Gluten free flour. Just two tablespoons of all purpose gf flour helps to thicken your vegan cheese sauce. We like King Arthur Measure-for-Measure Gluten Free Flour. That is, when we don’t have our homemade blend on hand.
- Nutritional Yeast. This healthy powder is the key to super cheesy vegan sauces. It has a similar umami flavor to parmesan, without any dairy. Plus, it packs tons of Vitamin B, which everyone (vegans and carnivores) should be getting more of.
Bring Texture into your Vegan Casserole with Mushrooms
Texture matters a lot when it comes to food. To me, a dish isn’t really complete if it’s all one mushy texture.
A casserole is one recipe that’s at risk for mushiness. It’s often cooked all together in a single, monotonous dish. Sure, they might have a crispy crust of breadcrumbs and cheese, like our spaghetti squash gratin has. But under that yummy crisp can be a lot of the same.
That’s why we upped the texture game in this plant based comfort food recipe. Adding sautéed mushrooms into the spaghetti squash casserole brings a totally new texture and delicous, almost meaty flavor.
You can use any kind of mushroom you like for this vegan casserole. I love the diverse flavors from mixed wild mushrooms. So I usually go for a variety pack at the store.
There are so many interesting kinds of mushrooms that bring their own flavor and shapes to the dish, why not experiment and try something new?
One note when you’re cooking the mushrooms for the spaghetti squash casserole. Mushrooms contain a lot of water. And you really can’t overcook them. So be sure to sauté them long enough to release as much moisture as possible before you add the cooked spaghetti squash.
Subs and Swaps
We made this baked spaghetti squash casserole recipe fully vegan and gluten free. If you’re not avoiding gluten, here are some easy swaps to make this recipe fit your diet:
- Gluten free flour can be easily swapped for regular all-purpose flour, tablespoon for tablespoon.
- Swap out gluten free breadcrumbs for regular breadcrumbs. We went with plain, unseasoned breadcrumbs. However, if you only have seasoned bread crumbs on hand, those will work.
- For vegan parmesan topping, we found that Follow Your Heart shredded dairy-free parmesan melted best on top of the casserole. Other vegan cheese options will taste great, but may not give you the gooey, melty topping you’re looking for.
- And if you’re not avoiding dairy, you can use the real thing to top your spaghetti squash casserole!
- Not a fan of mushrooms? They’re not necessary for the dish, though they sure do add delicious texture. If you skip the mushrooms, you might want to add another onion for flavor.
- Nut free? Soy milk will work in place of nut milk in the cheese sauce recipe.
Whether you enjoy this spaghetti squash casserole as a comforting weeknight dinner or a unique holiday side dish, we’re pretty sure you’ll give it two thumbs up. It may not be the most aesthetically pleasing dish, but it delivers on flavor. And that’s really all that matters, right?
If you give this vegan casserole recipe a try, we’d love for you to leave a rating and review below! We also love to see your creations on Instagram – tag us at @crowded_kitchen so we can see what you’ve been cooking.
This post contains affiliate links, which means that Crowded Kitchen may be compensated for purchases at no additional cost to you.Print
Creamy, cheesy vegan spaghetti squash casserole with wild mushrooms is the healthy comfort food recipe you’ve been looking for.
- 1 small spaghetti squash
- 2 tbsp vegan butter or olive oil, divided
- 1 sweet onion, sliced thinly
- 2 garlic cloves, minced
- 1 lb mushrooms of choice, sliced
- 1 cup cashew or non-dairy milk of choice
- 2 tbsp gluten free flour
- 2 tbsp nutritional yeast
- A few grates of fresh nutmeg, or a pinch of pre-ground nutmeg
- 1 tbsp fresh thyme, minced well
- 1 tbsp fresh rosemary, minced well
- ⅓ cup gluten free breadcrumbs (double if using a larger baking dish)
- ½ cup shredded vegan parmesan
- 1–1¼ tsp kosher salt, divided
- ¼ pepper, plus more for seasoning
- Preheat the oven to 375°F. Line a baking sheet with parchment paper. Butter an 8×8 inch baking dish.
- Cut the spaghetti squash in half, remove the seeds, and transfer to the prepared baking sheet, cut side down. Roast until fork-tender, 40-50 minutes, turning every 20 minutes. Remove the squash from the oven and let cool until you can handle it.
- Increase the oven to 400°F.
- Meanwhile, in a large nonstick skillet, heat 1 tbsp butter over medium heat. When hot, add the onion and garlic and sweat until translucent, adjusting the heat as necessary to avoid burning.
- Add the mushrooms to the skillet with the onions and cook until the mushrooms release their moisture, 8-10 minutes. Season with salt and pepper.
- Heat the remaining 1 tbsp butter in a small saucepan over medium heat. Add the nut milk and bring to a simmer. Reduce heat to low and add the flour, 1 tbsp at a time, whisking constantly, until thickened.
- Stir in the nutritional yeast, nutmeg, thyme leaves, ½ tsp salt and a pinch of pepper. Remove the sauce from the heat.
- Use a fork to separate the spaghetti squash into strands and add to the mushroom mixture along with 3 tbsp of bread crumbs. Stir to fully combine. Mix in the cheese sauce, turning on the heat to loosen it up while you stir. Taste and adjust seasoning with salt and pepper.
- Transfer the vegetables to the prepared baking dish. Sprinkle the remaining breadcrumbs and cheese evenly over the spaghetti squash.
- Bake for 8-10 minutes, or until golden on top and heated through. If the cheese isn’t well melted, cover the dish with aluminum foil and bake for 2-3 minutes more.
Keywords: vegan spaghetti squash casserole