There's not much to share... when you buy potatoes ask for those that do not stay like stones - even when cooked - but get a bit soft. Peel, cut and cook them in boiling salted water and apply a tiny, sharp knife to test when they are soft enough to be beaten into a mousse.
Remove the water from the pot and wait until they get a bit colder. Then start putting in milk (I always use the one that contains reduced fat - and you will see later why...) portion by portion while stirring until you've received a smooth mousse. Be careful: if the potatoes are still to hot the milk might coagulate.
Put in Salt, freshly grinded pepper (I always use white pepper), freshly grinded muscat (is has to be freshly grinded - makes a big difference) and some pieces of butter - enjoy the view how it slowly melts in the potatoes - almost sensitive... and there comes the bomb shell: wash, cut and remove the tiny seeds from as many piment pieces as you can bear, and cut them in small pieces. Put them in the mousse and enjoy!
For those who like things a bit less hot: don't put in piment but chose your favorite herb: persil or fresh sage or rosmarin etc...
DER WEG IST DAS ZIEL!