Foaming Sauce

A cold pudding sauce of the older school: raw beaten egg white folded into whipped cream, sweetened and spiked with sherry. The technique is straightforward, but the sauce is never heated at any stage, and that is where it fails a modern kitchen.

• Uncooked egg whiteThe egg white goes into the finished sauce raw and stays raw. Shell eggs can carry Salmonella on the shell and in the white as well as the yolk, and nothing in this method — not the sugar, not the tablespoon of sherry — brings the mixture to a temperature that would reduce that risk. For a foaming or hard sauce today, use a current recipe built on a cooked or pasteurised base.
• Held at room temperatureA raw-egg-and-cream foam left standing in a warm room is a growth medium; the risk is in the holding as much as in the ingredient.
• Powdered sugarIn American books of this period "powdered sugar" may mean a finely ground sugar rather than precisely what is now sold as confectioners' or icing sugar. If icing sugar is used, half a cupful is roughly 60 g.
• Thick cream"Thick cream" means cream rich enough to whip: broadly the equivalent of modern heavy or whipping cream. Gravity-separated dairy cream of the period may have been richer still.
• What "foaming" meantThe name describes the texture, not a cooked custard. Foaming sauce was a light counterpart to hard sauce, served with steamed and boiled puddings.
• YieldThe whipped cream and the beaten white together make a bulky, light foam; it collapses as it stands and is best used at once.