Slice boiled potatoes thin; chop some onion very fine; slice 2 hard-boiled eggs and mix. Sprinkle all with salt and pepper. Then heat some vinegar. Add a teaspoonful of made mustard and stir with the beaten yolk of an egg. Mix all together with 1 tablespoonful of hot butter and chopped parsley. Serve with cold meats.
A warm potato salad bound with a hot vinegar-and-yolk dressing rather than mayonnaise. The original gives almost no quantities, so treat it as a method and scale to what you have.
- Working proportionsFor about 1.5 lb (700 g) potatoes: 1 small onion, 2 hard-boiled eggs, 1/3 cup vinegar, 1 teaspoon mustard, 1 raw yolk, 1 tablespoon butter, a handful of parsley. That serves four as a side.
- The hinge: the yolk must not scrambleHeat the vinegar to just steaming, not boiling, then stir it into the beaten yolk off the heat in a thin stream. Poured the other way round, or over direct heat, the yolk curdles into threads and the dressing breaks.
- "Made mustard"Nineteenth-century shorthand for mustard already mixed with liquid, as opposed to dry mustard powder. Any prepared jarred mustard works; a sharp Dijon or a German-style mustard suits the Viennese context.
- Potato choiceUse a waxy variety, boiled in the skins and peeled while hot, so the thin slices hold together. Floury baking potatoes disintegrate into the dressing.
- Dress them warmWarm potatoes absorb the vinegar; cold ones sit in it. Slice and dress immediately after peeling, and let the salad stand ten minutes before serving so the flavour penetrates.
- VinegarA mild white wine or cider vinegar at around 5 percent acidity works well here. Undiluted distilled vinegar is sharper and can overwhelm the eggs.
- The raw yolkThe dressing is thickened by heat from the vinegar alone and never reaches a temperature that would pasteurise the egg. Use a pasteurised yolk if serving anyone who should avoid raw egg.
- ServingMeant as an accompaniment to cold roast meat or ham. It is best the day it is made; refrigeration firms the potato and dulls the dressing.
Warm potato salad dressed with vinegar, onion and a little fat rather than with mayonnaise is the older central European pattern, and it survives in Vienna as Erdäpfelsalat and in southern Germany as Kartoffelsalat, still served warm beside schnitzel or cold cuts. The egg-yolk thickening here is a common nineteenth-century trick for giving body to a dressing before bottled mayonnaise was on every shelf. The book's format explains the terseness: a dish for every day of the year, one per short paragraph, each labelled with a nationality so that a household cook could produce a year of variety from a single volume.