Preheat your oven to 400 degrees; take a 9x13 pan and spray it with cooking spray.

Let's start by making the vegan cheese. Grab a small to medium saucepan and add your potatoes, carrots, cashews, and enough water to cover it. Boil until soft (10-15 minutes); drain once cooked.

Take a high-speed blender, mix the remaining ingredients and the cooked vegetables, and blend until smooth. Set this aside until you're ready for it.

Take your potatoes and peel the skin off with a potato peeler or knife. Then slice the potatoes as thin and as evenly as you can. If you have a mandolin, this works really great but is also really sharp, so be very careful. Set these aside.

Take a small to medium pot and add 1 TB of the vegan butter and cook down the onions for about 5 minutes until cooked, then add the salt and pepper remaining vegan butter. Once it's melted in the flour and stirred with a whisk, it will clump up. Then add ¼ cup of the vegan milk and stir until mixed. Then add the remaining vegan milk and stir until starting to thicken for a few minutes.

Ccombine your cheese sauce and this roux until combined. Now take your prepared 9x13, add a layer of sliced potatoes, and sprinkle with a bit of pepper. Then layer half the cheese mixture, add the remaining potatoes, and repeat.

Bake in the preheated oven covered with foil for 30 minutes, then check with a toothpick poking the potatoes to see if they are cooked. If they aren't, cover again and cook at 15 minutes increments until cooked through. Then remove the foil and cook for 30 minutes. If you want the cheese to get that crispy look, put your oven on broil and cook for 5 minutes, watching closely, so it doesn't burn.

Let cool slightly before serving. These taste even better the next day.