On a cutting board, with a large knife, cut the bitter chocolate in small pieces.
Put it into the special pot and over a bain marie so that the chocolate melts.
When it melts, remove the pot from the bain marie and put it in the fondue pot which you have lit.
Slowly add the fresh cream and the 30 g of butter, stirring continuously.
Finally, add the 2 tablespoons of rum or brandy, depending on your preference.
When all the ingredients have become one, each person can dip a fruit of his preference into the chocolate.