Cream Dressing

Four lines of ingredients and no method, which was normal for a dressing every cook already knew. The whole trick is in how the acid meets the cream.

• The hinge: add the vinegar last, slowlyCream at this ratio will thicken and can break into curds if the vinegar goes in all at once. Whisk the mustard, salt and pepper into the cream first, then dribble the vinegar in while whisking, and stop when it looks the way you want it.
• Mustard means dry mustardMustard here most likely means dry mustard -- In a recipe of this vintage, a teaspoon of 'mustard' in a dressing is usually mustard powder rather than prepared jarred mustard. If you substitute prepared mustard the dressing will be milder and noticeably more vinegary.
• Cream means heavy creamUse 35% whipping cream. Half-and-half or coffee cream at 10-18% will not stand up to a full cup of vinegar and will read as thin and sour.
• The vinegar is probably sharper than intendedThe vinegar may be sharper than intended -- Household vinegar of the period was less standardized than today's 5% white or cider vinegar, and its strength is hard to pin down. Start with half the vinegar, taste, and work up; a full 1:1 ratio is aggressive by modern palates.
• Vinegar typeCider vinegar suits this best with cabbage, potato or bean salads. White vinegar gives a flatter, harsher result at this concentration.
• Yield and useAbout two cups, enough for a large slaw or a family potato salad. It is meant to be mixed and used the same day; refrigerate leftovers and expect it to separate, so whisk again before serving.
• No sugar, by designNo sugar -- Sweetened cream dressings do appear in period cookbooks, but this version has no sugar at all, so it is frankly sour on its own and depends on a sweet or starchy salad to balance it.