Dobos Torte

Steps

1. 1
   Heat the oven to 200°C. Draw a 22 cm circle on each of six sheets of baking paper and turn them over.
2. 2
   Beat the yolks with half the sponge sugar until pale. In a clean bowl, whisk the whites with the salt to soft peaks, then add the remaining sponge sugar gradually and whisk to stiff, glossy peaks.
3. 3
   Fold a third of the whites into the yolks, sift the flour over and fold it in, then fold in the rest of the whites and finally the melted butter, poured in at the edge of the bowl.
4. 4
   Spread the batter thinly inside the six circles, about 4 heaped tablespoons each, and bake one or two at a time for 6–8 minutes, until light golden. Peel off the paper while warm and trim each layer to a neat circle using a 22 cm plate as a guide.
5. 5
   For the buttercream, whisk the 4 eggs with the 200 g of sugar in a bowl over simmering water for 8–10 minutes, until thick and hot (70°C). Stir in the chocolate until melted and leave to cool to room temperature, then beat it into the softened butter a spoonful at a time.
6. 6
   Choose the neatest layer for the top and set it on baking paper. Melt the caramel sugar with the lemon juice in a dry pan over medium heat to a deep amber, pour it over the layer and spread it quickly to the edge with a palette knife.
7. 7
   While the caramel is still soft, cut it into 12 wedges with the buttered knife, pressing right through — once it sets hard it shatters instead of cutting.
8. 8
   Stack the other five layers with buttercream between them, then coat the top and sides and press the hazelnuts onto the sides. Pipe 12 small rosettes of buttercream around the top and lean a caramel wedge on each.
9. 9
   Chill for 2 hours, then cut along the caramel wedges with a hot knife.