Prep time: 20 minutes Makes about 1½ cups
Put xylitol in a blender or Vitamix and blend until it becomes powdered. If you don't blend it well enough, the frosting will taste grainy. Set aside. Process cashews in a food processor until they are powdered and starting to clump–don't go so far as to make cashew butter! Add coconut oil, lemon juice, hot water, and salt; process until smooth. Add coconut milk and blend as smoothly as possible, making sure to scrape down the sides of the food processor.
Put cashew mixture into a bowl along with vanilla and beat (with hand mixer). Slowly add in powdered xylitol. Taste frosting as you go along for desired sweetness. The more xylitol added, the stiffer the mixture will become. Once desired consistency is achieved, refrigerate.