In a high-powered blender or food processor, blend together all ingredients until smooth, stopping to scrape down the sides as necessary. Add more milk if until you want a thinner consistency.
Scoop dip into a bowl and serve with sliced fruit, pretzels, or graham crackers.
Leftovers can be stored in the refrigerator in an airtight container for up to 3 days.
Depending on the speed and power of your blender or food processor, this dip may take a little while to get completely smooth. Just keep blending, it will get there! Stop as needed to scrape down the sides with a spatula, and add more milk if necessary to get a thinner consistency. (I use this Cuisinart food processor, this Vitamix, or this KitchenAid blender)
Add the melted chocolate last, and place it on top of the black beans (if they are room temperature) so that it doesn’t harden again before you blend it.
Canned black beans tend to be softer than beans cooked from dry, so the dip will get smoother with canned beans.