Vegan Potatoes au Gratin

These creamy vegan potatoes au gratin are made with a rich cashew béchamel sauce. They’re the perfect winter holiday side dish.

Potatoes au gratin (pronounced “oh grah-TAN”, the French way) a.k.a. scalloped potatoes a.k.a. pommes dauphinoise (also French) are the ultimate comfort food for potato lovers. Layers of silky potatoes enveloped in a creamy, savory sauce, topped with crunchy breadcrumbs. It’s a super indulgent, très français way of cooking potatoes and always a crowd-pleaser.

Classic Julia Child-era gratin is made with milk and/or cream, butter, and lots of Gruyere cheese. But those of us who don’t cook with dairy can still make one as rich as the original – thanks to the mighty power of the humble cashew, as well as the combo of nutritional yeast and miso for that “cheesy” flavor. This vegan potato gratin is the perfect potato side dish for Thanksgiving and other holidays, as well as winter potlucks. Let’s dive in!

What’s In This Vegan Potato Gratin

The base of this dish is a cashew béchamel sauce – homemade cashew milk thickened with a roux (oil + flour). The béchamel is then flavored with rosemary, garlic, nutritional yeast, miso, and a pinch of nutmeg. The sauce then joins thinly sliced potatoes in a baking dish and everything gets topped with panko breadcrumbs.

Ingredients + Substitutions

• Cashews: Raw unsalted cashews create the creamiest sauce. Blanched almonds can be used as a sub. If you wanna skip making your own milk, you can experiment with store-bought unsweetened cashew milk for the sauce. (Avoid almond milk – its taste can be overpowering.) However, the success of this will really depend on the specific brand, so try it and let me know how it goes!
• Flour: For a gluten-free version, use a 1:1 GF flour.
• Nutritional Yeast: A “cheesy”-tasting seasoning sold in most supermarkets. Look for Bragg or Bob’s Red Mill brands. Lasts forever in the pantry so don’t hesitate to buy it if it’s your first time!
• Miso: This Japanese fermented soybean paste lends a savory “cheesy” flavor to this sauce and many other vegan dishes. It lasts forever in the fridge. If avoiding soy, double up on nutritional yeast in the sauce and compensate with an extra pinch of salt.
• Potatoes: Yukon Gold or white/butter potatoes work best here thanks to their waxy texture. Regular russet potatoes are a bit too starchy for gratin, but will technically still work. For a fun twist, sub with sweet potatoes.
• Panko Breadcrumbs: Japanese-style, extra-crunchy ‘crumbs. Sold in most supermarkets.

How to Make Vegan Potatoes au Gratin

Soak the Cashews: Start by combining raw cashews with boiling water in a blender, and setting them aside to soak for 30 minutes. This softens the cashews so they can be blended into a creamy milk.

Make Cashew Milk: Blend until the nuts are completely pulverized, 1 to 2 minutes.

Make the Vegan Cashew Béchamel: Heat oil in a pot and add flour. Cook, whisking almost constantly, until the mixture turns a pale blond color (this is called a roux). Then add the milk and whisk until the roux is fully dissolved. Bring to a simmer and cook gently until it’s thick enough to coat the back of a spoon (approximately the texture of crepe batter), 3 to 5 minutes. Remember to whisk frequently so it doesn’t burn on the bottom. Lastly, whisk in miso, nutritional yeast, rosemary, and a bit of nutmeg if you have it.

Assemble: Arrange peeled and sliced potatoes in a baking dish, and pour the sauce on top. Shake the pan a little to distribute the sauce all the way to the bottom layer of potatoes.

Bake: Cover with foil and bake until the potatoes are cooked through, about 1 hour. Lastly, uncover, sprinkle the gratin with the panko topping, and continue baking uncovered until the breadcrumbs are golden, about 15 minutes.

Make-Ahead Tips

Potatoes au gratin are best eaten while still warm from the oven, the same day as they’re made (otherwise, the topping gets soggy). If you want to prep this in advance, finish the sauce (through step 5 below) and refrigerate it for up to 3 days. You can also slice the potatoes and store them in a container full of water in the fridge for up to 24 hours. Re-heat the sauce before assembling and baking the gratin.

More holiday recipes this way…

• The Best Thanksgiving Salad
• Stuffed Portobello Mushrooms
• Balsamic Charred Brussels Sprouts
• Spiced Roasted Carrots

Let me know if you try this recipe! Give it a rating below and leave a comment, and don’t forget to tag your creation with @thenewbaguette on Instagram.

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