Prepare and shallow poach a whole sole with Fish Stock and mushroom cooking liquor. When cooked, place it on a dish, carefully remove the fillets and trim them neatly.
Break 1 egg into a basin, beat it well and add sufficient equal quantities of grated Gruyère and Parmesan cheese to make a stiff paste. Mix 1 tbs cold Sauce Bechamel into the paste and season with salt and a little Cayenne pepper.
Place 2 of the fillets side by side, coat them with an even layer of the prepared mixture
When ready, dip the whole re-formed fish into Sauce à la Villeroy, place on a tray and allow to cool and set. Trim carefully, flour, egg and breadcrumb and deep fry when required in very hot oil.
Drain, arrange on a serviette and surround with very green fried parsley.