Start by washing your celeriac and peeling off the roughest of the skin.
My celeriac was large, so it was cut into 2 parts, as I simply did not have enough salt to cover it.
Place them in a baking dish with the flat side down.
Cover them both in coarse salt and put them in the oven.
Cook them at 160 degrees Celsius (320 degrees Fahrenheit) in a conventional oven for 2.5 hours.
Take it out of the oven and break the new rock-hard salt crust. Use, for example, the back of a knife or spoon for this.
Brush off the excess salt, but be careful - the celeriac has become a bit brittle.
Cut it into coarse pieces and serve, for example, as a substitute for boiled potatoes with a main course.