You will need a saucepan with a steamer insert. Put the shallots in the saucepan with the white wine.
Rinse the gurnard fillets(*), rub dry and season with salt and pepper.
Place fillets on large chard leaves and mold into insert, along with mushrooms. Sprinkle with orange zest and sage, sprinkle a little parsley and tarragon evenly over the top.
Close the pot and let it boil, steam the fish for eight minutes over low heat, then remove the insert and keep the fillets and chard warm.
Add mushrooms to the stock form, and cook by half, using a tiny bit of cornstarch (mixed with a tiny bit of white wine) to pull off slightly. Before serving, stir in a tiny bit of freshly chopped parsley and tarragon.
Serve with: spring vegetables cooked in shallot steam.
(*) The long bones – seven pieces per fillet – can hardly be removed from the raw fish meat: take it in your stride, and pay attention to it during the meal!