Roast hazelnuts in the oven. Remove skins by rolling in a tea towel. NOTE: you can buy skin free hazelnuts if you prefer.
Blend all of the ingredients in a high power blender until smooth and silky, tasting and adjusting flavour and consistency as you go. NOTE: If using a food processor process the nuts first until it resembles nut butter, then add remaining ingredients and continue until you are happy with the consistency, adjusting flavour and liquid as needed.