If your hazelnuts are raw, roast them first: Spread them on a baking sheet and bake at 350°F (175°C) for 10-12 minutes, shaking the pan halfway through. Once they're fragrant and the skins are cracking, take them out and let them cool for a few minutes.
Rub the hazelnuts in a clean towel to remove as much of the skins as possible (it's okay if some stay on).
Add the hazelnuts to a high-speed blender and blend for 2-3 minutes until smooth and creamy, scraping down the sides as needed.
Add the powdered sugar, cocoa powder, vanilla, salt, and melted coconut oil. Blend for another 4 minutes until super smooth.
Pour into a clean jar. For a thicker, firmer texture, refrigerate for a few hours.
