Fillet and skin the monkfish tail. Remove any dark meat, discard, and then cut the fillets into 3-4 cm/1¼-1½ inch cubes. Shell the oysters over a bowl to catch the juices and briefly wash them in fresh water. To prepare the courgettes, cannelize them and cut across into rounds about 3 mm/⅛ inch thick.
Butter an ovenproof pan, put in the monkfish, fish stock, 120 ml/4 fl oz of the champagne and the reserved oyster juices (strain through muslin first). Season, cover with buttered paper or foil, and transfer to the