Nut Cookies (Eggs tablespoons boiling water)

A thin egg-foam batter carrying twice its weight in walnuts, piped or dropped onto a sheet. It behaves like a sponge batter rather than a creamed cookie dough, and that governs everything.

• The hinge: whip the eggs properlyThere is no butter and no leavening here, so every bit of lift comes from air beaten into the eggs and sugar. Beat until the mixture is pale and falls in a thick ribbon, then fold the flour and nuts in by hand so the foam survives.
• The boiling waterThe recipe does not say when the 1 1/2 tablespoons of boiling water goes in; hot water is usual in sponge-type batters, where it loosens the foam slightly and helps it flow from a bag. Adding it in a thin stream while beating is the safer course.
• Weights, since ounces are given3 ounces sugar is about 85 g, near enough to a scant 1/2 cup granulated. 3 ounces flour is also 85 g, which is roughly 3/4 cup of flour sifted before measuring — measure by weight if you can, as the batter is small and sensitive.
• Chop the nuts fineTwo cups of walnuts against 3 ounces of flour makes this almost a nut confection. If you intend to use a pastry bag, the pieces must be genuinely fine or they will jam the tip; a plain 1/2-inch opening or a spoon is safer.
• FlavoringThe recipe leaves this unspecified. Half a teaspoon of vanilla, or lemon extract or grated rind, would suit walnuts.
• Oven and timeThe recipe gives no temperature or time. Small piped cookies of this type will take a fairly moderate oven, around 350F, for roughly 10 to 12 minutes on parchment or a greased and floured sheet; take them out when the edges are brown and the centres just firm, as the high nut content burns quickly.
• Yield and storageThe recipe gives no yield; the quantity of batter will make a few dozen small cookies. They come off the sheet crisp and keep so in a tin, but will soften in humid weather.