1) Put 500 g of potatoes with the peel , previously washed, into a cauldron and cover them with cold and salt water.
2) Bring potatoes to the boiling point until skewering them with a toothpick they will result soft: then drip and peel them immediately.
3) Mash potatoes in a potato masher and gather all in a cauldron.
4) Cook the purée over a low flame, put a flush of hot milk and carry on cooking for 5/6 minutes.
5) Add to purée the nutmeg, the butter in small pieces and blend energetically. Put the purée in cocotte and dress with pesto with truffle.