Preheat your oven to 375. Lightly grease a 9x12-inch baking dish.
Cut your potatoes into ⅛ inch thick rounds. I didn't peel them first, but you can if you want to. You can cut the potatoes using a mandolin, or a knife. Add them to a large bowl.
Add all of the "cheese" sauce ingredients (cashews, water, lemon juice, nutritional yeast, ½ tsp salt, 2 tsp onion powder) into a high powered blender.*
Blend on high for 30 seconds or until the sauce is very creamy and no cashew chunks remain. Set the sauce aside.
Heat the ghee in a large skillet over medium heat. Add the minced garlic and stir for 1-2 minutes until fragrant.
Add in the coconut milk, chicken broth, "cheese" sauce, and additional 1 tsp sea salt. Whisk well over medium heat for a few minutes until the sauce bubbles and begins to thicken.
Layer ⅓ of the potato slices on the bottom of the casserole dish. Pour ⅓ of the sauce over top of the potatoes and use a spatula to spread it out evenly. Repeat this two more times until you have used up all of the potatoes and the sauce.
Cover the dish with foil and bake the potatoes for 30 minutes. Remove the foil, then bake for an additional 30-35 minutes until the casserole is bubbly and browned on top.
Serve with chopped fresh parsley. Enjoy!