Hard Sauce

A one-line recipe with one line missing: the ingredient list gives sugar and vanilla, but the method calls for butter that was never quantified. Everything else is straightforward creaming.

• The missing butterThe original omits the amount entirely, most likely a typesetting slip, since hard sauce is by definition creamed butter and sugar. Period recipes commonly run from about a third to a half cup of butter per cup of sugar, though some use more; the printed page does not tell us which was meant, so treat it as unknown rather than assume.
• Which sugarConfectioners' (powdered) sugar dissolves into softened butter and gives the smooth, opaque texture hard sauce is meant to have. Granulated sugar will stay gritty unless beaten a long while, and even then it tends to feel sandy on the tongue against a hot pudding.
• Butter temperatureThe butter must be genuinely soft but not oily — around 65F. Melted butter will not hold air and the sauce separates into a greasy pool as it sets.
• Why it is called hardThe sauce is chilled until firm, then served in a mound or cut in shapes, so that it melts on contact with hot pudding. Refrigerate at least an hour before serving; it is not a pouring sauce.
• Flavoring latitudeA teaspoon of vanilla is the plain version. Period cookbooks also print versions flavored with brandy, rum, sherry or a little grated lemon rind, added by the teaspoon and beaten in at the end so the emulsion does not break.
• Yield and servingA cup of sugar with the usual butter makes roughly a cup and a half of sauce, enough for six to eight servings alongside steamed pudding, mince pie or baked apples.
• StorageKeeps covered in the refrigerator about a week, and freezes well. Let it stand a few minutes before serving so it yields to a spoon without softening through.