Add potatoes, carrot, and onion to a boiling pot of water. Cook for 10 minutes or until fork-tender. Reserve two cups of boiled water, and drain the rest through a colander.
Add cooked vegetables, cashews, salt, pepper, garlic powder, onion powder, and nutritional yeast. Put 1 cup (235 ml) of reserved boiled water into blend. Blend until well combined. If a smoother texture is desired, add more of the boiled water.