Wash and peel the Jerusalem artichokes and cut them into even sized chunks. Add them to a large pan.
Finely cut the onion and celery stalks and add them to the pan as well.
Finally add the stock and bring everything to a boil. Cook the soup until the Jerusalem artichokes are soft.
Meanwhile, cut the mushrooms into thin slices. In a separate pan, cook the mushrooms in a little bit of oil. Cook them until they’ve reduced a little bit and have a bit of colour. Set them aside for now.
Once the Jerusalem artichokes are soft, take the soup of the heat. Using a (hand)blender, blend the soup until smooth.
Add the mushroom slices to the soup and warm through.
Season to taste with some freshly ground black pepper and serve!