Cut the celeriac into small pieces and place in a saucepan with the water. Add tarragon, salt and the spices and cook for about 10 minutes with the lid closed until soft.
In the meantime, cut the chestnuts into pieces and, when the celery is soft, add to the saucepan, then puree in the saucepan with a hand blender. Finally add the chickpeas, but do not mash them, and heat everything again.
Put freshly grated or ground nutmeg on the plates.
The amount is enough for 4 servings / people as soup. As a main course, it is sufficient for 2 people.