Preheat oven to 350 degrees. Lay the hazelnuts in a single layer on a baking sheet. Roast for 15-20 minutes, or until the skins start to crack and they start to smell toasted.
Remove from the oven and cool slightly. Place the hazelnuts on a dish towel and rub them until most of their skins come off.
Using a high speed blender and blend hazelnuts for several minutes, until they turn into a smooth butter.
Add the coconut sugar, cacao powder, vanilla, salt, and coconut oil to the blender and blend until well combined.
Taste and add a little maple syrup if you want it sweeter. If you want it runnier, add a little water to desired consistency. Combine well.
Spoon the mixture into a glass jar and store in the fridge.