The Hotel Sacher in Vienna is said to be the original home of the ultimate Austrian delight, the Sachertorte. It is a rich chocolate and hazelnut cake covered in a chocolate ganache.
Preheat the oven to 180°C/350°F/Gas 4. Grease and line two 20cm/8in square cake tins (pans). Cream the butter and sugar, beat in the eggs, then sift in the flour and fold it in with the hazelnuts, chocolate, vanilla extract, jam and crème fraîche.