This recipe was inspired by Yvette van Boven’s, celeriac main course (in Dutch) (Knolsederij met saus van citrus), and salt-dough crusted recipes such as Edie Eats  Dutch recipe. I made a dough of 1:1 flour and salt (300g flour, 300g salt), mixed with a bit of oil (2tbs) and sufficient water (150ml, but add untill sufficient) to make a nonsticky dough.
I cut off some of the lower parts of the celeriac, so that it would remain upright. Brushed oil to the celeriac, and wrapped it in the spread-out dough. I’ve added some rosemary sprigs and fennel seeds before wrapping the celeriac.

The celeriac can be placed in a hot oven (220 celcius) for about an hour, and then another 1.5 hour in a 130 celcius oven. I think it would be similar to put it in a 180 celcius oven for about 2-2.5 hours.

After the crust is hard, you can leave it for a few hours, as it keeps warm quite long. You may need to open the crust with a hammer, but peeling crust was quite easy (beware: may be hot!). I cut the celeriac in half, quarts, and cut away the outer 1cm of the veggy. The flavour was intense, but still mild. Combined with soft blue cheese made an excellent starter.