Coarsely chop the chocolate coating and melt in a hot water bath. Bring cream and coffee to the boil and remove from the heat. Melt butter and plate-fat in it. Stir in the couverture bit by bit.
Let it cool down at room temperature for about 2 hours until it is thick and creamy. Spray 1 tuff into each bowl (gr. hole nozzle). Cool for at least 1 hour.
Bring 1/4 l water to the boil. Add 1/4 l cold water. Put the writing tube in for about 5 minutes. Decorate pralines with it, sprinkle with pistachios. Store in a cool place