The day before, prepare the dried tomato petals by cooking peeled seeded tomatoes in a very low oven
Cut the chard leaves into strips. Cut the ham into small squares. Coarsely chop the hazelnuts. Cut the turbot lengthwise into sections, reserving the head and trimmings for the jus.
Jus: Brown the bones in olive oil; add the browned butter; Color them well; add the minced onion greens; Cook until very soft; Deglaze with sherry; reduce. Add the veal stock. Reduce to a silky consistency.
Garnish: Sweat the hazelnuts and tomatoes in olive oil; Add the chard leaves and cook until wilted; add the ham; Correct the seasoning. Sauté the turbot pieces in olive oil; Finish with butter; Once cooked, transfer to a rack.
Finishing and presentation: Place the garnish in the center of each plate; place the boned section of turbot on top; spoon on the sauce; Finish with fleur de sel, freshly ground pepper and chervil.