Vegan Potato Gratin

This creamy and indulgent vegan potato gratin is made with a rich cashew béchamel sauce. It’s the perfect Thanksgiving/winter holiday side dish. (This article has been updated from its original November 2018 version)

Potatoes au gratin (pronounced “oh gra-TAN”, the French way) a.k.a. scalloped potatoes a.k.a. pommes dauphinoise (also French) is the ultimate comfort food for potato lovers. Layers of silky potatoes enveloped in a creamy, “cheesy” sauce and 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 cooked together). 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.

Step-by-Step Instructions

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 Béchamel Sauce: Next, heat oil in a pot and add flour. Cook, whisking 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.

Ingredients + Substitutions

• Cashews: Raw unsalted cashews create the creamiest sauce. Blanched/slivered almonds can be used as a sub. If you wanna skip making your own milk, I advise using full-fat oat milk or store-bought unsweetened cashew milk for the sauce. Avoid almond milk – its taste can be overpowering.
• 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.
• 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!
• 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. For a fun twist, sub with sweet potatoes.

More festive plant-based recipes this way…

• Stuffed Portobello Mushrooms
• Roasted Cauliflower with Tahini and Dates
• Balsamic Charred Brussels Sprouts
• Carrot Fritters with Lemon Tahini

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 and @thenewbaguette on Instagram.

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