Method

• 1.
  Preheat the oven to 120°C. Grease and line the base and sides of three 24cm cake pans. Grease the pans again, then dust with a little icing sugar, shaking off any excess.
• 2.
  Place the brown sugar, cornflour and 1 cup (220g) caster sugar in a food processor and whiz until the mixture is combined and fine (without any lumps).
• 3.
  In the bowl of an electric mixer, whisk the eggwhites with a pinch of salt until soft peaks form. With the motor running, slowly add the sugar mixture, a little at a time, whisking until stiff and glossy. Fold in the vanilla and vinegar. Divide mixture among the pans, then transfer to the oven and bake for 1 hour. Cool completely in the switched-off oven with the door ajar.

• 4.
  Meanwhile, place the remaining 1/2 cup (110g) caster sugar in a pan with 1/2 cup (125ml) water. Stir over low heat until the sugar dissolves, then simmer, without stirring, for 2-3 minutes until thickened slightly. Cool, then add the berries. Transfer half the berry mixture to a blender and puree until smooth, then combine with remaining berry mixture and chill until needed.
• 5.
  Using electric beaters, beat the thickened cream and sour cream together until thick.
• 6.
  Run a knife around the rim of each cake pan, then carefully remove the cooled meringues and peel away the baking paper.
• 7.
  Just before serving, place 1 meringue on a cake stand, spread with one-third of the cream mixture and scatter with one-third of the berries. Repeat with the remaining meringues, cream and berries, drizzle with any remaining syrup, then serve immediately.