For the marzipan potatoes, first knead the marzipan, powdered sugar and rum.
Melt the chocolate in a bain-marie, mix with the nougat and allow to cool. Form small balls from the chocolate-nougat mixture and chill.
Form marzipan into a roll and divide into evenly sized pieces. Wrap chocolate-nougat balls in marzipan and roll into balls.
Finally, roll the marzipan potatoes in cocoa.