Melt the chocolate along with the butter in a large Bain Marie.
Combine the egg, sugar and coffee and add to the melted chocolate mixture and regularly stirring, cook for around five minutes (just until the sugar melts). Remove from the heat and allow to cool for a while.
Stir in whatever it is you are using and then place the bowl in the fridge for around an hour so it sets a little.
Pour mixture out onto a long piece of cling-film so you have a long, rough "sausage" shape. Roll up the cling-film and gently squeeze, roll and push until your "salami" is smooth and round. Twist the ends of the cling-film tightly. Put in the fridge for another hour.
Remove the salami and roll again to get it as round and smooth as possible. Place back in the fridge and leave overnight.
When ready to serve, sprinkle icing sugar over a piece of baking paper and roll the salami in it, brushing off any excess. Cut into thick slices.
Keep at room temperature (popping it back in the fridge if you don't eat it all in one go). Enjoy!