Salad Dressing

This is a cooked or "boiled" salad dressing, the standard mayonnaise substitute of the late nineteenth and early twentieth centuries. It thickens on egg yolk and a little flour rather than on emulsified oil, so the heat management is the whole recipe.

• The hinge: gentle heatEgg yolks with only two teaspoons of flour to protect them will scramble over direct heat. Use a double boiler with the water simmering, not boiling hard, and stir constantly until the dressing coats a spoon and reaches about 170F. Take it off the heat while it still looks slightly thinner than you want; it sets further as it cools.
• Tempering the yolksPouring the boiling lemon juice and oil into the yolks in a thin stream while beating hard is what keeps them from curdling. The comparison to "making frosting" means exactly that motion: continuous beating, slow addition.
• The saltSalt is listed but never assigned a step. Beat it in with the sugar and flour so it dissolves in the yolks rather than landing in the finished dressing as grit.
• A very tart dressingThree quarters of a cup of lemon juice against three tablespoons of oil is far sharper than any modern dressing. A few tablespoons of whipped or heavy cream stirred in when cold will bring it into a range most palates expect.
• Oil"Oil" in a recipe of this kind most likely means olive oil or a bland salad oil. With so little of it, the flavour of a strong peppery olive oil will dominate; a mild oil is the safer choice.
• Yield and keepingRoughly a cup and a half, enough for a large bowl of chicken, potato or fruit salad. Because it contains cooked egg, refrigerate it and use within three or four days.
• ServingIt is thick and pale, closer to a lemon curd than a vinaigrette. Best on firm ingredients that hold up to a heavy coating: cabbage, cold potato, cold poultry, or the moulded fruit salads popular when the book was written.