Spread the hazelnuts on a baking tray and toast until they are fragrant and light brown in colour (probably 15 to 20 minutes).
Allow to cool slightly then wrap in a tea towel, or paper towels, and rub to remove as many of the loose skins as you can (don’t fret about the bits that won’t come off).
While the nuts are still warm, place them, along with the chopped chocolate and maple syrup in a food processor.
Whizz until well chopped and reasonably fine – you may need to scrape the sides of the bowl down from time to time.
Start adding the oil gradually in a slow steady stream until you produce a spreadable consistency. It will thicken somewhat once packed, and if necessary can be microwaved very briefly prior to use.