In a pan, mix the diced grapefruit with the resulting juice, pomegranate juice, preserving sugar and water, bring to the boil, then boil fast for approx. 4 mins., set aside.
Thoroughly scrub the salsify under cold running water using steel wool, cut in half, place on a baking tray lined with baking paper. Drizzle with lemon juice and oil, mix and season.
Approx. 15 mins. in the centre of an oven preheated to 200°C. Remove from the oven, spread the jam over the salsify and bake for a further 10 mins.
Sprinkle the reserved pomegranate seeds, chervil and fleur de sel over the salsify.