Method

• 1.
  Preheat oven to 190°C/170°C fan-forced. Grease and line a 21 x 11cm cake tin. Place the butter and 115g dark chocolate in a small saucepan and stir over low heat until completely melted and combined.
• 2.
  Place the brown sugar, eggs and vanilla in a small bowl and whisk to combine. Sift the flour, baking powder, cocoa powder and pinch of fine salt into a large bowl, then fold through the egg mixture.
• 3.
  In a stand mixer fitted with the whisk attachment, whisk the egg whites and cream of tartar until medium peaks. Gradually add the caster sugar, then continue whisking for a further minute to dissolve the sugar and stablise the meringue.
• 4.
  Fold the melted butter and chocolate mixture through the cake batter. Gently fold through the meringue in three stages. Gently fold through the milk chocolate and remaining dark chocolate.
• 5.
  Transfer mixture to prepared tin and bake for 35-40 minutes, until a skewer inserted into the centre comes out clean. Set aside to cool to room temperature, then remove from tin.
• 6.
  For the Swiss meringue, combine all ingredients in a heatproof bowl placed over a saucepan of simmering water. Heat, while whisking, until mixture reaches 60°C.
• 7.
  Remove meringue from the heat and whisk in a stand mixer fitted with a whisk attachment until the meringue cools and reaches firm peaks. Spoon the meringue on top of the cooled cake, then spread with an offset palette knife or the back of a spoon to create some texture and peaks.
• 8.
  Toast the surface of the meringue with a kitchen blowtorch. Serve with raspberries.