Let the dates soak in water for 30 minutes.
To a food processor or blender, add all the ingredients and blitz until you get a sticky mixture.
Using a medium ice cream scoop or a tablespoon, scoop the mixture and roll into balls. Wet your hands slightly so that the dough does not stick to your hands. Store in the fridge while you melt the dark chocolate.
Place the ground hazelnuts and walnuts in a small bowl. To decorate, drop each ball in the nut mixture. Top each ball with a drizzle of dark chocolate.
Let chill for about an hour for a firmer texture and let the chocolate harden.