Chill some Nutella in the freezer for about 30 mins so it solidifies a little.
Add 1/2 of the hazelnuts, all of the Medjool dates, salt and cacao powder into a food processor. Process it until its mixed well
Add the rest of the hazelnuts and give it a quick blitz. Make sure to not over-process it. You want your remaining hazelnuts to stay pretty coarse so there's a good crunch to it.
Pop the mixture into the fridge for about 20 mins to chill.
To assemble the balls, take a palm-sized amount of your date mixture, roll it up into a ball then press down in the center until you create a little crater. Fill the crater up 3/4 of the way with your chilled Nutella, then press the sides back together to seal it up.
Give it another little roll to turn it back into the shape of a ball, repeat with the rest of your mixture and you're done!
Enjoy!