There are two versions of Poivrade Sauce. Both version are for meat, but one is for game in particular.
There is also a third, older version from the heyday of classical French cooking.
Version One for meat
A mirepoix of vegetables (e.g finely-diced vegetables) are softened in butter.
Wine vinegar and white wine are added in equal amounts, then simmered until the liquid is reduced by half.
Equal amounts of Espagnole Sauce and clear (aka white) stock are then added and simmered for an hour.
A few crushed peppercorns are added. The sauce is then simmered for a few more minutes (the sauce mustn’t be allowed to simmer too long after the peppercorns are added.)
The sauce is then strained, given the addition of a few more tablespoons of the clear stock, then reheated to serve.
Version Two for game (Sauce poivrade pour gibier)
A mirepoix of vegetables (e.g finely-diced vegetables) and small pieces of meat from the game it will be served with are softened in butter.
Wine vinegar and white wine are added in equal amounts, then simmered until the liquid is reduced by half.
Equal amounts of Espagnole Sauce and clear (aka white) stock are then added and simmered for an hour.
A few handfuls of mushrooms skins may be added partway through the hour of simmering.
A few crushed peppercorns are added. The sauce is then simmered for a few more minutes (the sauce mustn’t be allowed to simmer too long after the peppercorns are added.)
The sauce is then strained, given the addition of a few more tablespoons of the clear stock, then reheated to serve.
Old Version (used by Carême)
Simmer chopped onion, chopped carrot, chopped lean ham, parsley, thyme, mignonette (coarsely-cracked pepper), mace, vinegar, and consommé. Add more consommé along with some Espagnole Sauce. Simmer a few more minutes, then press through a sieve, and put back on the heat to reduce a bit more through simmering, then smooth out with a little butter.