Preheat the oven to 165C/330F and then roast the hazelnuts for 10 minutes. Remove from the oven and let cool for 10-15 minutes. If desired, you can remove most of the skins by wrapping the hot nuts in a clean tea towel for a few minutes and then rubbing the skins off with the towel.
Place the hazelnuts in the bowl of a food processor/high speed blender and blend for 5 seconds, then remove and set aside 2 tablespoons.
Add the remaining ingredients (except the reserved hazelnut pieces) in to the food processor and blend for a few minutes. Use a spatula to get any stray ingredients from the base and sides of the processor and then blend again for another minute.
Remove the mixture from the processor/blender and pour in to a clean glass jar. Add in the reserved hazelnuts and mix together using a spoon in the jar.
Storage: Will keep at room temperature for up to 3 weeks.