Break your chocolate into cubes, and place in a heatproof bowl. Pour a few centimetres of water into a saucepan and pop the bowl over the top. Make sure the water isn’t touching the bottom of the bowl- if you have too much, simply pour a little out.
Place over a low-medium heat and bring the water to a gentle simmer- your chocolate should start to melt. Stir it frequently, until all your chocolate is melted.
While a helper is melting the chocolate, pop your hazelnuts into a blender and whiz until they form a paste- this should take a few minutes. Make sure your blender doesn’t overheat!
Add your cocoa powder, vanilla extract, oil, salt, a tablespoon of powdered sugar and your melted chocolate. Pop in the blender and blend until well combined and smooth.
Pour into a jar and leave to cool. Store in the cupboard for up to two weeks and enjoy!