September 24, 2019

Cashew-Crusted Rosemary & Leek Vegan Potato Gratin

It’s dinner time, and tonight we’re eating potatoes! Vegan potato gratin with rosemary and leeks, topped with a soft cashew crust, specifically. Potato gratin is that magical moment where sliced potatoes are piled on top of each other in layers, and baked with a creamy sauce. The result is those individual potato layers meld- but not all the way. The distinct layers are still there, but the soft cooked potatoes form bonds with each other, making it almost seem like a single potato with flakey layers. However you think about it, in this dish aromatic rosemary blends with delicate, oniony leeks and cheesy nutritional yeast, all cooked in a garlic cashew cream with a soft cashew crust baked between layers of magical, magical potatoes. Just writing this is getting me hungry, so on with the post!

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About the Gratin

Potato gratin, also called gratin dauphinoise, is a French dish from the 1700’s. It was frequently eaten on Sundays, when women would prepare the gratin, place it in the oven at low temperature and let it bake while they attended Church. When they arrived home, warm potatoes and garlicky cream wafted through the house, and a hot meal was ready for dinner. There are different schools of thought as to which potatoes are best for potatoes gratin- some recommend starchy potatoes, as they’ll thicken the sauce. Others suggest waxy potatoes, as they’ll better hold their shape while cooking. I recommend using a medium-starch (or all-purpose) potato (such as Yukon Gold, Red Gold, and Kennebec) as they give you a little bit of both benefit. They’ll thicken the sauce, and still hold their shape after cooking. However, actually determining the starch content of the potatoes can be tough- they’re often just labeled by color (white, gold, red), so don’t stress it. Any potato will do.

Cashew Fails or Cashew Strengths

The first time I made this, I poured the cashew cream over the potatoes and immediately thought I had made a mistake. There was so much of it, and it was floating over the top of the dish rather than penetrating down through the layers like actual cream would have. But since I had already poured it, I put it in the oven anyways, hoping that while it cooked it would somehow drain through the layers and leave me with a picture-perfect vegan potato gratin recipe. After it cooked for an hour or so, I knew my hopes had been in vain- cashew, crusting the entire surface of my beautiful potatoes gratin. Better luck next time.

But then I tried some- not with any expectation, just because I don’t like wasting food- and my feelings about the cashew cream crust totally changed. It wasn’t a flaw, it was a feature. It added a soft, creamy, almost cheese-like topping to my simple potato dish, and added another layer of flavor. I guess sometimes we do have happy accidents, and the cashew-crusted vegan potatoes gratin recipe was born.

Like layers? Try one of these layered recipes!

How to Make Vegan Potato Gratin

The first tip I have for making this vegan potato dish is use a mandoline. It really changes life, when instead of slowly and painstakingly trying to cut super thin slices of potato, you can bang out perfectly thin and even slices in a few minutes. Once your potatoes are peeled and sliced, place them in cold water to stop them from oxidizing- but don’t drain that water, you’ll need it later. We actually use that potato-soaking water to make our cashew cream. It has a lot of starch from the potatoes in it, which helps to bind the layers together when it cooks. Making the cream involves boiling (or soaking ahead of time) cashews to make them soft and blending them with the other cream ingredients. Then the leeks need to be sautéed, and it’s time to assemble. Layer potatoes and leeks, ending by pouring the cashew cream over the dish- use your fingers to push down on top of the potatoes to let the cream sink down, but you’ll still be left with a good crust amount on top. Bake, and let it cool a little before serving.

Cashew-Crusted Rosemary and Leek Vegan Potato Gratin

Cashew-Crusted Rosemary and Leek Potato Gratin

Ingredients

2 lb. whole potatoes
1 large leek
1 tbsp. fresh rosemary
2 tbsp. nutritional yeast
Black pepper, to taste
Salt, to taste
1 cup raw, unsalted cashew pieces
½ lemon
1 large clove of garlic
1 tsp. salt
Olive oil, for cooking

Instructions

Preheat the oven to 375°F (190°C). Grease a 9-inch round cake pan and set aside (use a springform pan if you want to later remove the gratin from the pan). Place the cashews in a small pot and boil in water for 10 minutes (alternatively, soak for 4+ hours beforehand). Strain, and set aside.
Peel your potatoes, and use a mandoline to slice the potatoes to about 1.5mm thickness. Put the sliced potatoes in a bowl with 2 cups of cool water to prevent browning.
Chop the green parts off the leek and discard. Slice in half down the length and then slice into think halfmoons. Finely chop the rosemary as well. Heat a little oil in a small pan, and sweat the leeks with a pinch of salt until they’ve cooked down. Then add the rosemary, nutritional yeast and black pepper, take off the heat, stir and set aside.
Create the cream by blending the strained cashews, ½ lemon juice, garlic clove, salt, and 1 cup of the potato soaking water until smooth.
Assemble the gratin- start by adding a layer of potatoes to the greased pan, then sprinkle a heaping tablespoon of the leaks on top of the potatoes. Continue with another layer of potatoes, then more leeks, until you’ve run out, ending with a layer of potatoes. Pour the cashew cream on top, and smooth evenly on the potatoes. Use your fingers to push down on top of the potato layer to allow some of the cream to sink down into the layers.
Cover with foil and place in the oven for 1hour 15minutes. After 45 minutes, remove the foil. Remove from the oven and allow to cool for about 20 minutes before serving.

https://veryveganval.com/2019/09/24/cashew-crusted-rosemary-leek-vegan-potato-gratin/