Traditionally served at birthday celebrations in the city of Palermo in Sicily, the torta settevelli is seven layers (settevelli is Italian for ‘seven veils’) of chocolate and hazelnut in various guises. The result is a light, rich cake.
Make the génoise sponge. Heat the oven to 190°C/ 170°C/375°F/Gas 5.
Sift together the flour and cocoa powder three times until well combined. Place the sugar and eggs in a large bowl and whisk until thick and pale. Little by little, gently fold the flour mixture into the egg mixture, then fold in the melted butter.
Pour the mixture into the prepared cake tin and bake for 20–30 minutes, until risen and springy to the touch. Remove from the oven and set aside until cool enough to handle. Then, turn out onto a wire rack to cool completely.
For the sugar syrup, tip the sugar into a small pan. Add 75ml of water to the pan and bring to the boil over a medium heat, stirring until the sugar dissolves. Then, boil until reduced by half to a syrup consistency. Remove from the heat and add the hazelnut liqueur. Set aside.
To make the praline paste, heat the sugar and 4 tablespoons of water over a medium heat until the mixture reaches 121°C/250°F on a sugar thermometer. Stir in the toasted hazelnuts, then tip out the praline onto a silicone mat and leave to set.
When the praline is brittle, snap off a small piece (about 5cm square). Place the remainder in a food processor with the hazelnut oil and blitz for 3–4 minutes to a fine paste. Set aside.
For the hazelnut bavarois, soak the gelatine in cold water until soft. Pour the milk, 200ml double cream and 175g of the praline paste into a pan and heat until just under boiling point.
Whisk the egg yolks and caster sugar together until pale and creamy. Pour the hot milk mixture over the eggs and whisk together. Return the custard to the pan and cook until the mixture coats the back of a spoon (82C). Remove from the heat.
Drain the gelatine, squeezing out any excess moisture and stir it into the custard until it dissolves. Cool, stirring over an ice bath to room temperature. Whisk 450ml double cream to soft peaks, then fold into the cooled custard in 3 stages. Set aside.
For the praline layer, melt the chocolate and butter in a heatproof bowl set over a pan of gently simmering water. Remove from the heat and add the feuilletine and remaining praline paste. Set aside.
To assemble the torta, line the sides of the tin with acetate (over the baking paper). Trim the sponge flat and then slice the sponge in half horizontally. Place one slice in the bottom of the cake tin and brush with half of the sugar syrup.
Spoon the praline layer over the sponge and smooth with a palette knife. Then, ladle over half of the hazelnut bavarois. Place the semi-assembled torta in the freezer for 15 minutes.
Place the second slice of sponge over the set bavarois and brush with the remaining sugar syrup. Ladle over the remaining bavarois, then freeze for 45 minutes.
Meanwhile, make the chocolate mousse. Pour 150ml of the double cream into a small pan and bring to just below boiling point. Pour over the chopped chocolate and stir to a smooth ganache. Leave to cool to 37°C/99°F on your sugar thermometer. Meanwhile whisk the remaining 250ml of cream to soft peaks and fold into the cooled ganache, one third at a time.
Remove the cake from the freezer and take it out of the tin. Place the cake on the cake card, then spoon the chocolate mousse over the cake and smooth the top and sides. Freeze for 30 minutes.
Start the decoration. First, temper the chocolate. Melt the chocolate in a heatproof bowl set over a pan of simmering water until it reaches 45°C/113°F on a cooking thermometer. Remove from the heat and cool to 34°C/93°F. Place the sheets of acetate over the damp baking sheet and smooth them out completely. Spread an even layer of chocolate over the acetate, then run the scraper over the chocolate to create strips.
Before the chocolate sets, lift the acetate strips with the tip of a knife and curl them so they look like opened toilet paper tubes. Set the curled, coated acetates in the baguette moulds.
For the chocolate mirror glaze, soak the gelatine in cold water until soft. Put 80ml of water, and the cream, cocoa powder and sugar in a pan and bring to the boil, stirring continuously. Once the mixture boils, bring to 103°C/217°F on the sugar thermometer, then remove from the heat.
Drain the gelatine, squeezing out any excess, and stir it into the glaze until dissolved. Leave to cool.
Remove the torta from the freezer and place on a wire rack set over a baking tray. Slowly pour the glaze over the top and sides of the torta, to coat.
To decorate, roughly chop the reserved hazelnut praline and sprinkle on the top of the torta. Peel the chocolate twists from the acetates and pile them up in the middle of the torta. Lift the torta off the cake card and transfer to a cake stand to serve.