Perch, Silesian Style

Draw and clean two or three fine perch, but do not scale them. Put some water
in a saucepan with a bunch of parsley, a little vinegar and salt and boil it; then plunge
the perch into it and boil for twenty minutes. Make the following sauce: Put in a
stewpan two tablespoonfuls of vinegar, a few sprigs of parsley, a little tarragon, two
chopped shallots, a bay leaf, and four or five peppercorns. Boil the liquid till reduced
to half its original quantity. Leave it till cool, then mix with it a teacupful of melted
glaze, the beaten yolks of six eggs, four ounces of butter and a little salt, stir the
sauce over a very slow fire to thicken without letting it boil. Place the same in a
bain-marie and whisk it, adding gradually some small pieces of butter. When frothy
put in a teacupful of brown sauce and about two tablespoonfuls of grated horseradish.
Remove the perch carefully with a skimmer, scrape the scales off, dip the fish in the
cooking liquor, then wipe them in a cloth; put them in a hot dish, pour the prepared
sauce over them, first mixing with it a little chopped parsley and a few capers and
serve. Care must be taken to remove the scales quite cleanly or they will spoil the
dish.