Cover cashews fully with water (I think I soaked in about 2 cups water). Soak for 2.5 hours minimum, or overnight if you plan ahead. Drain, and then dump into blender with water, lemon juice, salt, apple cider vinegar, garlic powder, hemp seeds and fish. *Fish is optional, if you don't add it they'll still be delicious!* Blend until smooth. You can easily turn this into a vegetarian plate by substituting 1/3 cup of pollock for 1/3 cup of cooked navy beans. Fill mushroom caps, and set into glass 13x9 pan. Pour broth around mushrooms, then sprinkle with pepper. Bake at 350 F for 20 mins.