Hard Sauce

A two-ingredient creamed butter sauce for hot puddings, written for a kitchen with no electric mixer. The whole point is aeration, and the only real work is the beating.

• Weights, not cupsTwo ounces of butter is half a stick; four ounces of powdered loaf sugar is roughly 1 cup of confectioners' sugar, depending how it packs. The 1:2 butter-to-sugar ratio by weight is the thing to preserve.
• Powdered loaf sugarLoaf sugar was refined sugar sold as a solid cone and crushed as needed, so "powdered" here means finely ground table sugar rather than the modern cornstarch-cut confectioners' product. Either works; superfine gives a slightly less chalky finish, confectioners' sugar dissolves more readily into cold butter.
• SpidulaEvidently a variant spelling of 'spatula' (cf. French spatule): a flat wooden paddle or stiff spatula, not a rubber scraper. A wooden spoon does the same job.
• Twenty minutes of beatingThat is a hand figure. In a stand mixer with the paddle, five to seven minutes on medium-high will take the butter pale and light; the mace then needs no more than a minute to distribute.
• Butter temperatureFresh butter should be soft enough to take sugar without breaking but not greasy — around 65F. Too cold and it never aerates; too warm and the sauce weeps when it hits a hot pudding.
• MaceHalf a coffeespoonful is a scant quarter teaspoon. Mace is the outer aril of the nutmeg, warmer and less resinous than the seed; ground nutmeg at the same quantity is the usual substitute.
• "Place it on the ice"Refrigerate, and only briefly — two minutes in an icebox is a firming, not a chilling. Shape the sauce first, since it stiffens quickly and will crack if worked cold.
• YieldAbout three-quarters of a cup, enough for four to six servings alongside a steamed or plum pudding.