Vegan Baked White Sauce Spaghetti

Last Updated on July 13, 2025

A Vegan Baked White Sauce Spaghetti that is a great alternative to a red sauce Baked Spaghetti.

Not only is this dish vegan, it’s also gluten free!

I love making baked spaghetti’s, they are simple, easy to make, and take much less time than regular spaghetti on the stove.

With this baked spaghetti, I added fresh mushrooms and spinach, but this dish is easily customizable.

Other fresh vegetables will compliment this dish nicely, such as fresh picked peas, asparagus, Brussels sprouts, baby broccoli, or sauteed ribbon zucchini and carrots.

You can also add different herbs to this dish, such as fresh chives, dill, sweet or lemon basil.

Every time you make this baked spaghetti, why not try whatever vegetables and herbs that are in season for a completely new dish every time!

Ingredients for the baked spaghetti

• Spaghetti Noodles – I used a gluten free spaghetti noodle. You can use your favorite spaghetti noodle.
• Oil – I used olive oil in my dish. Use your favorite oil.
• Mushrooms – I used a baby portabella. Use your favorite mushrooms. Try different mushrooms such as crimini, shiitake, or the white button.
• Onion – I used a vidalia onion in my dish. A onion powder can be used as a substitute.
• Spinach – I sauteed fresh spinach with the mushrooms, onion and garlic. Don’t like spinach? Try fresh peas, zucchini, asparagus, Brussels sprouts, carrots, or baby broccoli.

Ingredients for the white sauce

• Raw Cashews – Widely used in a lot of vegan recipes today, because of it’s mild flavor and creamy texture. Cashews work wonderfully as a replacement for dairy in so many different ways.
• Lemon Juice – I add lemon juice to this recipe to help thicken the sauce but also to give the sauce a little something extra. You will not taste the lemon, but I really don’t know how to explain it. I think it brings out the flavor in the sauce.
• Oil – In this recipe I used olive oil, but any oil will work just as well. The oil will give the sauce a velvety texture.
• Water – A key ingredient to thin out the sauce, making the sauce thin enough to pour over the noodles.
• Garlic – I used a minced garlic in the sauce. This can be substituted with fresh garlic cloves sauteed with the onion. Garlic powder can be a substitute or eliminate garlic all together.
• Cornstarch – This helps thicken the sauce.
• Miso – I like to use miso in my sauce. Miso adds a salty and deep umami flavor to the sauce. One Substitution can be a vegetable broth instead of the water.
• Plant Based Milk – I used an unsweetened plain almond milk in the sauce. Use your favorite plant based milk.
• Seasonings – Salt and Pepper to taste.

How to make the Vegan Baked White Sauce Spaghetti

Making the white sauce

In a medium sized bowl, add the raw cashews, and fill the bowl with hot water until the cashews are covered, then set aside for no less than 4 hours.

After 4 hours of soaking the cashews, drain and rinse.

Add the cashews to the blender along with the other ingredients.

Blend until the sauce is nice and velvety-smooth, set aside.

Preheat the oven to 400°F.

Add the spaghetti noodles to a 9×13 baking dish.

Drizzle oil over the noodles and move around to coat each noodle (this helps to somewhat keep the noodles from sticking together).

Next clean and drain the fresh spinach.

Clean and slice the fresh mushrooms.

In a large skillet, add enough oil to cover the bottom of the skillet, place the sliced mushrooms in the oiled skillet.

Saute the mushrooms on a medium high heat until they are soft.

Stir in the fresh spinach.

Pour the mushroom mixture onto the oiled spaghetti noodles.

Next pour the white sauce over everything and slightly mix everything together.

Place the dish into the oven and bake for about 30 minutes.

After 30 minutes, remove from the oven and stir the noodles around making sure the noodles are not stuck to the bottom.

If the noodles are soft you will not need to return to the oven.

But if the noodles are still slightly hard, return the dish to the oven and bake for another 10 to 15 minutes.

Check at 10 minutes, if the noodles are still slightly hard, return to the oven for 5 or more minutes.

Continue baking until the noodles are soft.

Once the noodles are soft, remove from the oven and enjoy while the dish is still hot!

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