Slit open the vanilla pods and scrape out the pulp. Dissolve the coffee powder in 1 tablespoon of hot water, mix with rum, vanilla pulp, Nutella and powdered sugar, ideally in a blender or carefully with a hand mixer.
Chill the mixture overnight, then whip the cream until it is semi-stiff the next day and stir in.
Fill into bottles (e.g. 3 bottles of 0.5 l each), close tightly and refrigerate. Always shake well or stir if necessary before serving, it will always be a little firmer at the top.
According to official information, it can be kept in the refrigerator for approx. 3 weeks, but I have also drunk a much older and still excellent liqueur, the rum is very well preserved.