Sachertorte is a Viennese chocolate cake from 1832: a dense, not very sweet sponge with a thin layer of jam under the glaze. The usual failure is a dry, crumbly sponge. The cause is over-baking and too little fat or egg.
What it is made of
Top to bottom:
- Dark ganache 0.5 cm
The coating
- Sacher sponge ×2 · 2.5 cm
- Raspberry jam 0.4 cm
A thin layer
Two sponges, a layer of jam, ganache.
An honest note on how this differs from the original. The Viennese cake uses apricot jam, which is also brushed over the outside before glazing, and the glaze is a chocolate sugar glaze that sets firm. Here the jam is raspberry and the finish is ganache. What changes: raspberry is sharper and brighter, apricot milder and more neutral; ganache is softer and never sets to a crisp shell. It is traditionally served with unsweetened whipped cream.
Order of work
Sponge (the day before): melt the chocolate with the butter, beat the yolks with sugar, and beat the whites separately to soft peaks (stiff ones are hard to fold in). Cool the chocolate mixture until warm, fold in the yolk mixture, then the whites with a spatula in two additions, then the flour. Mix as little as possible or the foam collapses. Bake at about 170 °C until a skewer is dry. Cool 10 to 15 minutes in the tin, then on a rack. Let it rest a day and it slices cleanly.
Jam: cook raspberries with sugar until thick. For the layer, sieve the jam to remove the seeds and spread it thin while warm. Its role is not only flavour: it separates the sponge from the ganache and adds acidity.
Assembly:
- Bottom sponge, thin layer of jam, top sponge.
- Trim the edges and, if you like, brush the sides and top thinly with leftover jam; this seals the crumbs.
- Chill 30 minutes.
- Ganache: bring cream (30% or more) to 80 to 90 °C, pour over chocolate, add cold butter at the end. Pour at about 34 to 36 °C onto a cold cake. The drips run for about two minutes; let them settle.
What can go wrong
- Dry sponge. Over-baked, or the whites were over-beaten and would not fold in evenly.
- Collapsed sponge. The foam was folded too long, or the oven door was opened.
- Cracked ganache. Poured onto a very cold cake, or the ganache was too thick.
- Jam bled through. The layer was too thick or too runny.
The verdict
Sachertorte is a sponge you must not over-bake and a thin layer of jam. Chocolate and smooth ganache are the other half.