For the hazelnut truffles, melt butter in a saucepan and stir in granulated sugar. Allow to caramelize (brown) slightly, deglaze with whipping cream and continue stirring until everything has boiled together.
Remove from heat. Then stir in the chocolate. Cool the mixture well, when completely cold, whip with a hand mixer and pour into a piping bag fitted with a large star nozzle.
Fill 20 confectionery capsules with one hazelnut each. Pipe the mixture on top and sprinkle the hazelnut truffles with grated hazelnuts.