Scorzonera is not actually related to Salsify, though one of its synonyms is “Black Salsify.”
Scorzonera has black skin. Above ground, its leaves are spiny and broad. Though it is usually sold with the tops off, the leaves can be used as a salad green.
Scrub. Don’t cut unless very large. Peel, then boil for 30 minutes. Cook two pounds (1 kg) for 6 people. It will discolour when peeled or cut, so either work quickly or place into water with some lemon juice as you proceed.
If you find it fiddly to peel, you can cook then peel. If you go this route, reheat after peeling either in a steamer or microwave.
After it’s cooked, to serve you can toss in lemon juice, or mash with a bit of butter and cream, and then top with some grated cheese and breadcrumbs and then bake a bit.