Vegan Mushroom Tart

This vegan mushroom tart is a savory tart with a store-bought crust, a creamy cashew-and-silken-tofu custard, and a layer of pan-fried mushrooms, zucchini, and onion. It bakes up light and golden, and it works as a main dish, a snack, or a slice you pack for lunch. No eggs, no dairy, no meat, and no one at the table will miss them.

Savory tarts are lovely, aren’t they? Tarts have a long history of being more than dessert — they were served as main dishes in old English kitchens, starting out as nothing more than a dough casserole for heavy fillings. But today I’m not going to show you how to make a heavy tart. I don’t think we’re exactly trying to replace anything here, because mushrooms are absolutely delicious on their own and deserve some credit. I say vegan because we aren’t using animal products, but to be fair, you’ll be able to serve this to your non-vegan friends and family and they won’t even notice or care that it doesn’t have milk, eggs, or meat.

What goes into this tart

The filling is built on two things that make it creamy without a single egg: soaked raw cashews and silken tofu. Blended together with soy milk, they turn into a smooth, custard-like base that sets in the oven. Nutritional yeast brings a savory, faintly cheesy note, cornstarch helps the custard firm up as it bakes, and garlic, fresh thyme, salt, and black pepper carry the flavor.

For the vegetables, you’ll use sliced mushrooms, a zucchini, and a red onion, all pan-fried before they go into the tart. Onions and mushrooms go together like best friends in many of my favorite recipes, and who can blame simple kitchen chemistry? The crust is store-bought to keep this quick — just make sure to grab a vegan one if you want to keep the whole tart plant-based, since some pre-made crusts contain butter.

Choosing your mushrooms

I believe this tart is at its best when made with a mix of different sorts of mushrooms. Cremini, shiitake, and oyster mushrooms go along very well together — each brings its own texture and depth, so the filling never tastes flat. Plain white button mushrooms work perfectly well too if that’s what you have on hand.

When you shop, look for mushrooms that are firm and dry to the touch, with caps that aren’t slimy or shriveled. Slice them evenly so they cook at the same rate. And if you love cooking with them as much as I do, they’re the star of my cream of mushroom soup with thyme and my basic stuffed portobello mushrooms too.

Why soaking the cashews matters

Soaking the cashews overnight is the step that makes the biggest difference to the texture of the filling. Raw cashews are hard, and a food processor alone will leave you with a grainy, gritty base no matter how long you run it. Once they’ve soaked for several hours, they soften enough to blend into something completely smooth and creamy, which is exactly what you want when it sets alongside the silken tofu.

If you forget to soak them the night before, a quick fix is to cover them with just-boiled water and let them sit for about 15 to 20 minutes while you fry the vegetables. Drain them before blending. Combined with the cornstarch, this smooth base is what lets the custard hold its shape once baked.

Tips for the perfect tart

Pre-baking the crust is worth the extra few minutes. Pricking it thoroughly with a fork and baking it before the filling goes in keeps the bottom from turning soggy under the wet custard. This is the difference between a crisp slice and one that falls apart.

Cook the vegetables in batches rather than crowding the skillet. When you pile everything in at once, the mushrooms and zucchini release water and steam instead of browning. Fry the zucchini until lightly golden at the edges, then the mushrooms until golden on both sides, then the onion until wilted — setting each aside as you go. Those golden edges are where a lot of the flavor lives. When you pour the blended filling into the crust, tuck the cooked vegetables in, then bake for about 35 minutes until the top is lightly golden and set. Let it cool before slicing so the custard has time to firm up, and finish with fresh chives on top.

What to serve with it

A slice of this tart is filling on its own, but it really shines next to something fresh and light. A crisp green salad or a bowl of soup rounds it into a full meal — I love it alongside my cream of mushroom soup when I want to lean all the way into the mushroom theme. If you’re building a bigger vegan spread, it sits happily next to my vegan mushroom lasagna, and a spoonful of homemade stretchy vegan mozzarella on the side never hurts.

Storing and making ahead

This tart keeps well, which makes it a great candidate for meal prep. Once fully cooled, cover it and store it in the fridge for up to 3 to 4 days. The custard actually firms up nicely after a night in the fridge, so cold slices hold together beautifully for lunch. Reheat individual pieces in the oven or a toaster oven for a few minutes to bring back some crispness in the crust; a microwave works in a pinch but softens the pastry.

You can also prep components ahead: fry the vegetables and blend the filling the day before, keep them separately in the fridge, then assemble and bake when you’re ready. If you’re on a mushroom kick, my mushroom crepes and brown rice mushroom pilaf are two more make-ahead-friendly favorites to round out the week.

I hope you’ll enjoy making this vegan mushroom tart as much as I enjoyed telling you how to make it! If you try it, come back and rate the recipe, and leave a comment telling me which mushrooms you used and whether you went with the zucchini or swapped in something else. Make sure to tell me how everyone liked it!

Vegan Mushroom Tart

A savoury vegan tart with golden mushrooms, zucchini and sweet fried onions over a creamy cashew and silken tofu filling, all in a crisp pie crust. It takes about 70 minutes from start to finish, plus soaking the cashews ahead of time.

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Rate

Prep Time 10 minutes minutes

Cook Time 1 hour hour

Total Time 1 hour hour 10 minutes minutes

Choose Serving Size 6

Ingredients 

• 1 sheet vegan pie crust store-bought

For the filling:

• 1 cup silken tofu
• 1 red onion sliced
• 2 cups mushrooms sliced
• 1 zucchini sliced
• ¾ cup raw cashews soaked overnight
• ¾ cup soy milk unsweetened
• 2 cloves garlic
• 2 Tbsp nutritional yeast
• 3 Tbsp cornstarch
• 1 tsp thyme fresh
• ½ tsp black pepper freshly ground
• ½ tsp salt
• 2 Tbsp olive oil
• 1 Tbsp chives chopped

Instructions

• Preheat the oven to 200 C.
• Press the crust into the pie pan and prick it thoroughly with a fork. Pre-bake the crust at 200 C until it is set and just barely coloured.
• Heat a large skillet with 1 Tbsp olive oil over medium heat.
• Add the zucchini to the skillet in a single layer. Fry for about 4 minutes per side, or until lightly golden on the edges. Remove the cooked zucchini from the pan and set aside.
• Add the remaining 1 Tbsp olive oil to the same skillet, add the sliced mushrooms and cook for about 6 minutes, or until lightly golden on both sides. Remove the mushrooms from the skillet and set aside.
• Add the sliced onion to the same skillet and fry for about 5 minutes, until wilted. Set aside.
• Add the silken tofu, drained cashews, soy milk, garlic, nutritional yeast, cornstarch, thyme, salt and pepper to a food processor.
• Blend until smooth.
• Pour the mixture into the pre-baked pie crust. Top with the onion, zucchini and mushrooms, then bake for about 35 minutes, until lightly golden.
• Let the tart cool, then serve with the chopped chives scattered on top.

Notes

Check the label on your pie crust – many store-bought ones contain butter, so pick a certified vegan sheet. The cashews must be soaked (overnight, or 15-20 minutes in hot water) or the filling will not blend smooth. Keep leftovers covered in the fridge for up to 3 days and reheat in the oven to bring the crust back to life; the tart is just as good served at room temperature.

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