Small Sauces: Normandy

To 1 qt (960 mL) fish velouté add 4 oz (120 mL) mushroom cooking liquid (or 4 oz/120 g mushroom trimmings) and 4 oz (120 mL) oyster liquid or fish fumet. Reduce by one-third. Finish with liaison of 4 egg yolks and 1 cup (240 mL) cream. Strain and swirl in 3 oz (90 g) raw butter.