In a small bowl soak the cashew in hot water for 20 minutes. Drain and rinse then add them to a powerful blender together with 1.25 cups of water, the lemon juice, garlic powder and nutritional yeast. Puree until smooth and creamy. Season to to taste with a pinch of sea salt and refrigerate until needed.
Make the Scalloped Potatoes:
Slice the leeks lengthwise then chop them up. Add them to a bowl with cold water. Stir to rinse well and allow them to stay in the water for a few minutes. All the grit and dirt will fall to the bottom of the bowl. Use your hands to scoop out the leeks from the water and drain them on a kitchen towel.
Preheat a large skillet on medium low flame. Add a splash of water and the leeks with a pinch of sea salt. Saute until wilted and they start to get some color adding more water if needed as not to burn them, about 10 to 15 minutes Adjust seasonings to taste with more sea salt and black pepper. Set aside.
Meanwhile use a mandoline to thinly slice the potatoes. Rinse well in some cold water and dry on a tea towel. Sprinkle all over the top with a good pinch of sea salt and black pepper.
Lightly oil a large gratin dish including the sides. (You can use 2 small gratin dishes if you wish)
Layer the thinly slice potatoes on the bottom of the gratin dish overlapping each other. Spoon the sauteed leeks and spread them on top of the potato slices. Sprinkle with the fresh thyme.
Pour the cashew cream over the leeks and give the dish a little shake. Sprinkle with the fresh chives or dill and a pinch of red pepper flakes.
At this point you can top with your favorite vegan cheese, loosely cover with aluminum foil and bake in the preheated oven for 45 minutes. Remove the foil and cook another 10 minutes or so until the cheese has melted. To brown the top you can transfer the gratin under the broiler flames for a few minutes until golden to your liking, just make sure that you are using a broiler proof dish.
Remove the potatoes from the oven and allow them to set for a few minutes before serving.
Video
Notes
You can omit oiling the baking dish and line it with parchment paper instead.
If your potatoes aren’t sliced paper thin make sure to adjust the cooking time and bake an additional 20 to 25 minutes or so until the potatoes have completely softened and cooked through.