Makes 50 truffles: 500 g of dark chocolate, 75 g of butter, 75 g of icing sugar, 125 g of fresh cream, 100 g of sugar-free cocoa, 1/10 litre of Negrita rum, 2 tablespoons of strong coffee.

Break the chocolate up into pieces and melt it in a double boiler with the coffee. Once the chocolate has all melted, add the fresh cream and the butter in slivers. Take off the heat and whisk thoroughly. Add the icing sugar and Negrita rum. Leave it to stand in the fridge for 1 hour. Make little balls of chocolate with a spoon. Coat half of them in icing sugar and the other half in cocoa. Put them on a plate. Cover them with cling-film and leave them in the fridge for a week before eating them.