I'm sorry I couldn;t deliver sooner.
Here is Barbara Maher's Sachertorte and i'll copy out the whole introduction and all. Typing quickly so there will be typos.
As she so authoritatively describes it it really seems to be a "genuine' and "original" version.
Apart from black forest kirschtorte, this is probably the best-known chocolate cake in the world, and is instantly recognizable with its simple flat shape and a plain undecorated chocolate covering with "Sacher" piped across the centre; it seems incredible that it should have been covered to the point of legal action being taken to claim the rights to the ooriginal recipe
The nbame is closely associated with the Sacher family of vienna. Franz Sacher had relinquished his position as chef to the Austrian Chancellor Cl;emens Lochar Metternich in 1840, so that he could open a delicatessen shop and hotel in the Weihburggasse. His three sons took over the vaerious responsiblities on his retirement, and the youngest, Eduoard, established himself in the gastronomic history of Vienna as the founder of the hotel which was named after him, in the 1880s. As an exclusive speciality of this hotel, Franz Sacher's Torte helped establish its fame and reputaqtion. The hotel became a rendezvous for the aristocracy, for the Hungarians and Bohemians and eventually even the Archduke and Duchess. And the torte also ousted the Linzertorte from its hitherto premier position as favorite.
The closely guarded seecret of the Sachertorte recipe meanwhile inspired an extraordinary variety of "authentic" versions. The most popular were based on an equal weight mixture and others included almonds. Maybe at last the truly authentic recipe has come to light.
Thhis recipe was given to a lady attending cookery clases conducted by Anna Sacher, Eduoard's wife, in 1883. It used the old measures, which i have converted to grammes.
Anna Sacher;s Sachertorte (1883)
140 g dark plain chocolate (my note - this usually means semi sweet cooking chocolate in europe)
100 g butter
140 g caster sugar (my note: fine sugar)
4 egg yolks
4 egg whites
70 g plain flour
gas 3 170 C, 325 F /60 minutes
Set the chocolate in the oven on a plate to warm and melt gently,. cool slightly. Beat the butter and sugar in a bowl until pale and fluffy then beat in the choclate. Weat in the egg yolks one at a time and combine well. Whip up the egg whites to a stiff snow and mix lightly into the chocolate mixture with a metal spoon. Fold in the seived flour carefully, taking care not to lose any air. Have ready a 22 cm (1 1/2 inch() springform tin, greased and floured. Pour in the mixture, rap the tin on the work top to dispel any air pockets, and bake in the preheated oven. Cool on a wire rack and then cover with a plain chocolate icing. You may like to coat the cake first with apricot jam to insulate it against the chocolate"
From Barbara Maher: Cakes, Penguin Books (1982) p. 149-150
That was her recipe. I'll add the chocolate icing below from her book.
To ice a 22 - 24 cm (9 inch) cake
160 gm plain chocolate
250 ml water
1 tbsp butter
140 gm preserving or granulated sugar
Melt the chocolate with 2 tbsp of water in a small fireproof bowl in the oven or over a pan of simmering water. Stir in the butter until smooth. Boil the remaining water in a copper sugar boiler to the pearl stage (104C 221F); draw away from the heat and plunge the pan into a bowl of cold water so that the sugar stops cooking. Pour immediately over the melted chocolate and stir with a wooden spoon until the right texture is achieved (a metal cooking sppn should stay lightly coated with icing). Not all the sugar syrup may be needed. When the icing starts to cool a little, pour it over the cake. Set in a hot oven for just a few moments for the icing to set and to take on a high glaze. Cool at room temperature, never a cold place, as this causes a grey-white bloo,m to appear.
From: Barbara Maher, Cakes. Penguin books 1982 page 74
This book is wonderful and apparently out of print, alas. mine is paperback and is falling apart and is just a bunch of pages loose in a taped together cover.
It has the BEST tarte tatin and the best dobostorte (really unusual filling)