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.
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 with Spinach and Farro
- Massaged Kale Caesar Salad
- Balsamic-Glazed Charred Brussels Sprouts
- Carrot Fritters with Lemon Tahini
This rich vegan potato gratin with creamy cashew béchamel is an indulgent potato side dish for Thanksgiving and other gatherings.
- ¾ cup raw cashews (see note below)
- 3 cups boiling water
- ¾ teaspoon fine sea salt, divided
- 3 tablespoons extra virgin olive oil, divided
- 2 tablespoons all-purpose flour
- 2 tablespoons nutritional yeast, divided
- 1 tablespoon miso
- 1 garlic clove, crushed or finely minced
- 1 sprig rosemary, leaves picked and minced
- 1/8 teaspoon freshly grated nutmeg (optional)
- Freshly ground black pepper, to taste
- 2 1/4 pounds Yukon Gold or butter potatoes (about 6 medium potatoes), peeled and thinly sliced
- 1/4 cup Panko breadcrumbs
- Place 3/4 cup cashews in a blender and cover with 3 cups boiling water. Set aside to soak for 30 minutes.
- Meanwhile, preheat the oven to 375ºF.
- Add ¼ teaspoon salt to the blender and puree until the mixture turns into milk and the cashews are completely pulverized, 1 to 2 minutes.
- Heat 2 tablespoons oil in a medium saucepan over medium-low heat. Whisk in 2 tablespoons flour and cook for about 1 minute, whisking constantly, until the roux is pale blonde. Whisk in the cashew milk. Bring to a boil while whisking frequently to prevent burning on the bottom of the pot. Then reduce the heat to low and simmer until the sauce is thick enough to coat the back of a wooden spoon, still whisking frequently, 3 to 5 minutes.
- Turn the heat off and whisk in the 1 tablespoon each nutritional yeast and miso, 1 crushed garlic clove, 1 sprig minced rosemary, 1/8 teaspoon nutmeg (if using), lots of pepper, and ½ teaspoon salt. (It’s okay if the sauce tastes too salty at this point because it will flavor the potatoes).
- Arrange the potatoes in an 8×8” baking dish (or similar). Pour the sauce on top and tap the dish on the counter a few times to distribute the sauce to the bottom. Cover with foil. Bake until the potatoes can be pierced easily, 50 to 60 minutes.
- Meanwhile, in a small bowl, combine 1/4 cup Panko, 1 tablespoon nutritional yeast, 1 tablespoon oil, and a pinch of salt. Rub the mixture together with your fingers to distribute the oil evenly.
- Uncover potatoes and sprinkle with the Panko mixture. Bake uncovered until golden brown, 15 to 20 minutes more. Let stand for 5 minutes before serving.
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.
- Serving Size: 1/6 of the recipe
- Calories: 244
- Carbohydrates: 35.5 g
- Fiber: 5.3 g
- Protein: 5.5 g
- Cholesterol: 0 g
Keywords: vegan, potatoes, cashews, thanksgiving, gratin