Sauce based on chopped shallots with vinegar and stock, "a proper sauce for turkey, or any other sort of white fowls." (Glasse 1747, Moxon 1764, Eaton 1822).

Original Receipt in 'English Housewifry' by Elizabeth Moxon, 1764 (Moxon 1764)

11. To make POVERADE.
Take a pint of good gravy, half a jill of elder vinegar, six shalots, a little pepper and salt, boil all these together a few minutes, and strain it off. This is a proper sauce for turkey, or any other sort of white fowls.