Clean the Jerusalem artichokes with a brush then peel them.
Peel the onion and cut it into pieces.
Cut the Jerusalem artichokes into cubes.
Brown the onion in a little oil then add the Jerusalem artichokes.
Cover with water and simmer for 20 minutes.
Mix the preparation. Salt and pepper.
Add the cream and mix again.
Grate the truffle and add it to the velouté. To mix together.
Grate the truffle and add it to the velouté. To mix together. (Keep 4 slices of truffles for decoration)
Crush the hazelnuts.
For the dressing, pour the velouté into a bowl, add a few hazelnuts and the truffle slices.