Lemon Sauce
2 teaspoons arrowroot or corn- 1 cup sugar starch 2 cups water grated rind and juice one lemon 1½ tablespoons butter Mix arrowroot and cornstarch with sugar. Add boiling water and cook twenty minutes. Add flavoring and butter.
Serve hot. 2 egg yolks
A plain boiled dessert sauce for puddings, thickened with starch rather than eggs. The ingredient list runs in two columns, so read it as: 2 teaspoons arrowroot or cornstarch, 1 cup sugar, 2 cups water, the grated rind and juice of one lemon, and 1½ tablespoons butter.
- Arrowroot or cornstarch, not bothArrowroot or cornstarch -- the ingredient line offers a choice, though the method as printed reads "Mix arrowroot and cornstarch with sugar." Arrowroot sets clearer and glossier and tolerates acid better; cornstarch gives a slightly cloudier, more opaque sauce.
- Two teaspoons is very little thickenerTwo teaspoons of starch to two cups of water yields a thin, pourable sauce meant to be spooned over a steamed or baked pudding, not a lemon curd. If you want it to coat the back of a spoon, closer to 2 tablespoons is needed.
- Mix the starch with the sugar firstThis is the hinge. Rubbing the starch through the dry sugar separates the grains so the boiling water can be added without lumps; adding water to bare starch will seize it.
- Twenty minutes is longer than neededTwenty minutes is longer than modern practice requires -- starch reaches full thickening power within a minute or two of the boil, and long cooking here mostly drives off raw starch flavour; five to eight minutes over gentle heat is ample. (The lemon goes in afterwards, so there is no acid in the pan during the boil.)
- Add the lemon at the endThe recipe adds the flavouring after cooking. Lemon juice added early can break down starch, particularly arrowroot, and the rind's aromatic oils are volatile. Stir in the rind, juice and butter off the heat.
- Butter finishes itSwirl the butter in without returning the pan to the boil, so it emulsifies into the sauce rather than separating into a slick on top.
- YieldSomething over two cups once the sugar is dissolved, enough for six to eight servings alongside cottage pudding, gingerbread or a steamed suet pudding.
Cornstarch-thickened dessert sauces filled a specific gap in the turn-of-the-century American kitchen: they gave a hot, glossy accompaniment to plain steamed and baked puddings without the cost, care or curdling risk of an egg custard. Arrowroot, imported chiefly from the West Indies, was the older and more genteel thickener and was long recommended for invalid cookery; cornstarch was the cheaper domestic substitute that is generally said to have displaced it through the late nineteenth century, though the recipe here still offers arrowroot first, and books of this era commonly print the two as interchangeable. Lowney's book appears to have been published by a chocolate manufacturer, and its dessert chapter is built around the puddings and cakes such sauces were meant to dress.