In a single layer, bake the hazelnuts for 20 minutes.
Wrap the hazelnuts in a clean towel and rub vigorously for a few minutes to remove the skins.
Pour the hazelnuts into a food processor (discarding the skins) and blend on high.
Slowly add the Irish cream liqueur and the double cream.
Take off the lid and add the icing sugar, cocoa powder, and melted chocolate, then blend again until smooth. (Unless you have a very good quality food processor, there will be little bits in there - which simply add texture!)
Transfer into your favourite jar, where it will keep in the fridge for up to 2 weeks!
Spread on crusty bread and crepes, or stir 1 heaped tablespoon into 250 millilitres (1 cup) of warm milk for an indulgent hot chocolate!