For the cognac truffles, beat the yolks and powdered sugar until fluffy, heat the whipped cream and stir into the yolk mixture. Soften chocolate and add to yolk-cream mixture with cognac.
Chill the mixture for a few hours and let it set. Whip, pour into a piping bag and pipe into praline molds. Refrigerate the cognac truffles.
Preparation Tip:
The cognac truffles can still be decorated with a pistachio, for example.