Reform Sauce is based on the version of Poivrade Sauce made for game (Sauce poivrade pour gibier.)
It is served with lamb, mutton or game.
What is truly daunting about Reform Sauce is realizing that in order to make this sauce you first had to make Poivrade Sauce, and that in order to make the Poivrade Sauce, you first had to make Espagnole Sauce.
There is a modern day version floating about whose ingredients are chicken stock, ham, butter, onion, carrot, red wine vinegar, port, cornstarch (aka cornflour in the UK), juniper berries, cloves and mace. Though this is clearly quite different from the classic one (see below), one can understand why attempts have been made to bypass having to make two other sauces before you could make this one.
1 hard-boiled egg white
2 cooked mushrooms
1 oz (25g) pickled tongue
1 small cooked truffle
All the above are to be julienned (cut into thin strips), then added to 1 cup (1/2 pint / 250 ml) of Poivrade Sauce. The Poivrade Sauce should not be allowed to boil after these ingredients are added.
Invented by Alexis Soyer sometime in the 1830s at the Reform Club, still extant today (2007) on Pall Mall in London.
Named after the club.