For the cream of Jerusalem artichoke soup with porcini mushrooms, place the porcini mushrooms in cold water. Peel the Jerusalem artichoke tubers and cut them into small pieces. Wash the celery, put the green aside.
Clean the stalks and cut them into fine slices. Peel and dice the onion.
Heat 30 g butter in a saucepan. Sauté Jerusalem artichokes, celery and onions in it. Add the ground hazelnuts. Add the stock and cook for 15-20 minutes.
In the meantime, squeeze the porcini mushrooms well, chop them finely and sauté them in oil.
Heat the chicken stock, add the whipping cream, season with pepper and salt and bring to the boil once. Stir the remaining butter into the stock, a little at a time. Stir the poultry stock well with a whisk, season again to taste.
Arrange the Jerusalem artichoke cream soup with porcini mushrooms and celery greens and serve.