Vegan Spaghetti Squash Casserole with Mushrooms

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 Microwave.

Microwaving is the fastest way to go from whole, raw spaghetti squash to fully cooked strands. Here's how to do it:

1. Fill a shallow baking dish or even a wide bowl with about an inch of water.
2. Place the spaghetti squash inside the dish, and microwave for 5 minute increments.
3. 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.

Ingredients

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.

1. 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.
2. Gluten free flour. Just two tablespoons of all purpose gf flour helps to thicken your vegan cheese sauce.
3. 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.

Texture matters a lot when it comes to food. To me, a dish isn't really complete if it's all one mushy texture.

That's why we like to add crunch to puréed soups, like our Thai Red Curry Pumpkin Soup with Crispy Tofu. And nut brittle to Vegan Pumpkin Mousse.

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.

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