Melt the chocolate in a water bath and remove from heat. Cream the butter in a baking bowl. Add the powdered sugar by the spoonful. Beat with the whisk of a hand mixer until smooth. Melt coffee powder in coffee liqueur and add. Add slightly cooled chocolate, stirring slowly. Continue mixing until a uniform thick cream is formed.
Pour into a piping bag fitted with a nozzle. Pipe the cream into the praline molds. Decorate each praline with a halved pistachio. Keep wrapped and cooled.
Tip: Feel free to use better chocolate – the more delicious the result!