Preheat oven to 160 degrees. Roast hazelnuts for 10 minutes. Allow to cool. Peel the skin of the nuts by rubbing them together with your hands.
Place sugar and vanilla sugar in the food processor and whizz for 30 seconds! Add roasted hazelnuts and cacao powder and grind in food processor for 15 seconds.
Transfer the mixture into a pot add the milk and heat for 2-3 minutes while stirring. Add dark chocolate chunks and melt into the mixture by stirring. Transfer chocolate mixture back into food processor and mix to a smooth, creamy consistency.
Transfer into a sterilised jar and close tight. Once cooled down store in refrigerator where it can last for a couple of weeks.
Double the amount of ingredients. Put half of the finished spread into a jar and pipe the other half into little bite-size chocolate bites using small cupcake forms. Keep in the freezer for treat time!