1. Place salt and lemon juice in the bottom of a large bowl.

2. Rinse the celeriac root and remove as much dirt as possible with a brush. Using a large, sharp chef’s knife, remove the skin, cutting away the twisted roots. Working quickly (the root will discolor if exposed to air too long), quarter the root and shred finely in a food processor. Add the shredded celeriac to the bowl containing the salt and lemon and toss well, making sure all of the pieces are coated. Leave to tenderize for 20 minutes while preparing dressing. The lemon juice will protect it from browning.

3. Place another bowl over a pot of warm water on the stove, warming the bowl (like a double-boiler). Add mustard and water and whisk well. Gently drizzle in the oil and whisk to emulsify—take your time so the dressing doesn’t "break". Dribble in the vinegar, whisking all the while. Add salt.

4. Rinse the shredded celery root with fresh water and dry well, rolling it in paper towels and squeezing out as much water as you can. Put it back in the bowl (dry the bowl, too) and add the dressing and toss well. Fold in the Veganaise and parsley.

Note: You can eat it immediately, but this refrigerates well. The longer it is refrigerated, up to a few days, the more tender the celeriac gets.