Preheat oven to 350°F (175°C) and roast hazelnuts on a baking sheet for 10 minutes until skins begin to crack.

Transfer warm nuts to a clean towel and rub to remove skins; discard skins and cool nuts slightly.

Process hazelnuts in a high-speed blender for 5-8 minutes until they reach a liquid butter consistency.

Add cocoa powder, sweetener, vanilla, and salt to the blender.

Process on medium speed until the sweetener is fully integrated and the texture is glossy.

Stream in coconut oil while processing to reach the desired emulsion and smoothness.

Transfer to an airtight glass container and store at room temperature.