Soak the cashew for 30 minutes (or over night) in warm water, so they can be blended more easily later
Peel the onions and the potatoes and cut them in big pieces. Add both in a pot and fill with water until the vegetables are covered with it, add some salt. Let it boil for about 15 minutes until the potatoes are done. Pour the water away
Put the vegetables together with all the other ingredients in a blender blend until the mixture has the desired consistency. Season it with pepper, salt and/or the other spices
Simmer the mixture in a pot until the consistency is satisfying. Season again with salt, pepper, nutritional yeast or lemon juice