In a food processor, process peanuts until very fine.
Add in dates, peanut butter, vanilla and salt and process until a dough starts to form.
Roll into balls and then press a hole into the ball with thumb. Then press to flatten the cookie.
Place on plate or parchment lined dish.
In a small bowl, whisk all ingredients for the chocolate filling together.
Spoon the chocolate into the thumbprint holes of each cookie. If you use the extra 2 tsp. of cacao, this will be spreadable as well like a frosting.
Let chill for about 20-30 minutes so chocolate can set.