Take the spawn and pound it in a mortar with the butter, until quite smooth, and work it through a hair sieve. Put the Béchamel into a stewpan, add the pounded spawn, the lemon-juice, which must be strained, and a plentiful seasoning of cayenne and salt; let it just simmer, but do not allow it to boil, or the beautiful red colour of the sauce will be spoiled. A small spoonful of anchovy essence may be added at pleasure.
Time: 1 minute to simmer.
Sufficient for a pair of large soles.
Seasonable at any time.