Soak the dates in the milk or water for 10-30 minutes to soften. In a blender, add the avocado flesh, dates, milk, vanilla and salt and cacao powder. Blend until smooth. You may need a little more liquid to facilitate blending and scrape down the sides of the jug a few times.
Adjust ingredients to taste, adding more cacao powder if it needs it. Serve and garnish with your choice of toppings.