Dobos torte

This Hungarian sponge cake, layered with chocolate buttercream and topped with caramel, is named after its creator, József Dobos, a chef from Budapest.

SERVES 14

PREPARATION TIME: 1 hour 30 minutes, plus cooling and chilling COOKING TIME: about 30 minutes

FOR THE BUTTERCREAM 400g granulated sugar 200ml double cream 75g dark chocolate 350g salted butter, softened, plus extra to grease

FOR THE CAKE

10 medium eggs, separated, plus 2 medium egg yolks 400g caster sugar 1tbsp lemon juice

1tbsp vanilla extract 100g ground hazelnuts

100g plain flour

FOR THE CARAMEL SHARDS 200g caster sugar

40g blanched hazelnuts

1 Start with the buttercream. Over a gentle heat, in a large pan, heat sugar and 100ml water, stirring until sugar dissolves. Turn up the heat and boil until it is a dark golden caramel. Remove from heat and whisk in cream (it will froth up). Set aside to cool completely. 2 Melt chocolate in a heatproof bowl set over a pan of gently simmering water. Set aside to cool for 10min.

3 Using a freestanding mixer (or a handheld electric whisk and large bowl), beat the butter until light and fluffy. Add the caramel a splash at a time, beating well after each addition. Put two-thirds of the buttercream into a piping bag (or transfer to a separate bowl). Fold the cooled chocolate into the remaining buttercream, transfer to a second piping bag (or leave in bowl) and set both aside in a cool place (not the fridge).

4 Preheat oven to 200°C (180°C fan) mark 6. Grease a 23 x 33cm Swiss roll tin and line with baking parchment. For the cake, with a handheld electric whisk or freestanding mixer, beat 12 egg yolks and sugar until pale and thick, about 5min. Add lemon and vanilla and beat for 1min. Add ground hazelnuts and ½tsp fine salt. Beat to combine. Use a large metal spoon to fold in flour in 2 batches until combined.

5 In a separate large bowl and with a clean whisk, beat the egg whites to stiff peaks. Add a few spoonfuls of egg white to the yolk mixture and stir well to loosen it, then gently fold in the remainder of the whites with a large metal spoon. Pour half the batter into the prepared tin and level with a palette knife. Bake for 10min, or until the sponge is firm and golden.

6 Using the baking parchment, lift the sponge on to a wire rack to cool. Line the tin with fresh parchment and cook remaining batter as before.

7 Once the sponges are cool, with a long side closest to you, cut each one vertically into thirds. To assemble, lay a sponge on a serving plate, then pipe or spread a fifth of the chocolate mixture on top in an even layer. Repeat 4 times (to use all the chocolate buttercream), then lay on the final sponge. Trim edges to neaten. Gently spread a thin layer of caramel buttercream over top and sides of cake (a crumb coat). Chill for 30min.

8 For the shards, slowly dissolve the sugar in a heavy-based pan. Turn up heat and boil to a dark golden caramel. Quickly pour on to a lightly greased baking sheet and scatter over blanched hazelnuts. Cool completely, then break into shards.

9 Spread the remaining buttercream over the top and sides of the cake and smooth with a palette knife dipped in hot water. Chill for 20min, then top with the shards.