Marjolaine

Ingredients

For the dacquoise

• 125g (4½ oz) blanched almonds
• 125g (4½ oz) blanched hazelnuts
• 300g (10½ oz) caster sugar
• 25g (1 oz) cornflour
• 6 large free-range egg whites (reserve the yolks)

For the chocolate ganache

• 270ml (9½ fl oz) double cream
• 360g (12½ oz) plain chocolate, 46% cocoa solids, broken into pieces

For the praline

• 300g (10½ oz) caster sugar
• 100g (3½ oz) blanched almonds

For the buttercream

• 225g (8 oz) caster sugar
• pinch cream of tartar
• 8 free-range egg yolks
• 350g (12 oz) unsalted butter, slightly softened, cut into pieces

To assemble

• 150g (5½ oz) flaked almonds
• 50g (1¾ oz) hazelnuts, chopped
• 50g (1¾ oz) pistachios, slivered

Instructions

1. 1
   Preheat the oven to 350F. Line two 12x8in Swiss roll tins with baking parchment.
2. 2
   For the dacquoise, tip the almonds and hazelnuts into the bowl of food processor and pulse until finely ground. Spread the ground nuts out in a layer on a baking tray and roast for 10 minutes, stirring every 3 minutes until golden-brown. Transfer to a large bowl and leave to cool. When cool, stir in 100g (3½oz) of the caster sugar and the cornflour. Reduce the oven temperature to 300F.
3. 3
   Pour the egg whites into the bowl of a free-standing electric mixer fitted with a whisk attachment and whisk on medium speed for about 2 minutes, until the egg whites are opaque and frothy. Increase the speed and add the remaining 200g (7oz) caster sugar, a spoonful at a time, to make a stiff, glossy meringue. Gently fold the toasted nut mixture through the meringue.
4. 4
   Divide the meringue equally between the Swiss roll tins and spread out evenly using a palette knife. Bake for 45–60 minutes, until light golden-brown and firm to touch. Turn off the oven and open the oven door so it is just ajar, then leave the dacquoise inside until completely cool.
5. 5
   Remove from the oven and carefully invert onto a sheet of baking parchment. Carefully remove the baking parchment from the bottom of the meringues.
6. 6
   For the chocolate ganache, Pour the cream into a pan and heat until just simmering. Pu the chocolate in a heatproof bowl and pour over the cream. Stir until the chocolate is melted and the mixture is smooth. Leave to cool and then chill the ganache until thick enough to spread and pipe.
7. 7
   For the praline, line a baking tray with non-stick baking paper. Combine the caster sugar and 100ml (3½fl oz) water in a pan over a medium heat, stirring until the sugar dissolves. Increase the heat and boil, without stirring, until the caramel turns golden-brown or reaches 340F on a sugar thermometer (CAUTION: boiling sugar is extremely hot. Handle very carefully. Use a deep pan to avoid bubbling over.). Meanwhile, toast the almonds in a dry pan until golden-brown. Remove sugar syrup from the heat and add the almonds, stir well and tip onto the prepared tray. Leave to cool. Break up the praline into pieces and blend to a fine powder in a food processor.
8. 8
   For the buttercream, pour 5 tablespoons water into a heavy-based pan with the sugar and cream of tartar. Bring to the boil and boil rapidly until it reaches 240F on a sugar thermometer (soft ball stage). Pour the yolks into the bowl of an electric mixer fitted with the whisk attachment. With the mixer running on medium speed, gradually pour in the sugar syrup, taking care not to splash the syrup onto the beaters. Continue whisking for 5-10 minutes until the mixture is thick and completely cool. Gradually add the butter bit by bit, whisking continuously. Fold in the praline powder and chill until needed.
9. 9
   To assemble, toast the almonds and hazelnuts in a dry frying pan until golden-brown. Using a very sharp knife, cut the dacquoise sheets in half lengthways so you have four sheets each measuring 12x4in. Place one sheet of meringue on a serving plate and spread with one quarter of the buttercream. Top with a second sheet of meringue and spread with one third of the ganache. Top with a third sheet of meringue and spread with another quarter of the buttercream. Top with final sheet of meringue.
10. 10
    Spread the remaining buttercream over the top and sides and press the toasted flaked almonds onto the sides of the gateau. Spoon the remaining ganache into a piping bag fitted with a small (no 33) star nozzle. Pipe the chocolate ganache around the top edge of the cake and in five diagonal lines, across the top of the cake. Fill the gaps between the diagonal piped lines with alternating hazelnuts and pistachios.