Select a gratin dish of about the right size for the fish. Cover the bottom of this with a bed of sliced potatoes. Wash the fish and pat it dry, then place it on this bed, season it and pour a little melted butter over it. Next cover the fish with half a dozen slices of lemon, followed by a layer of sliced potatoes. Repeat the seasoning and melted butter. Pour 150 ml (5 fl oz) of white wine over all.

Put the dish into a preheated moderately hot oven (400°F, 205°C, gas 6) and let it cook for 30 to 35 minutes, basting every 5 minutes or so and making sure that the liquid remains sufficient. Sprinkle with chopped parsley before serving.

The title of this dish commemorates Antoine-Auguste Parmentier, who was largely responsible for introducing the potato into French cuisine, in the 1780s. The same dish, or something very like it, may also appear under the names Saint-Pierre à la Menagère or (with onion as well as potato) Saint-Pierre des Pêcheurs.