Method

1. For the hazelnut meringues, dry-fry the hazelnuts in a frying pan over a medium heat for 4-5 minutes, or until toasted and golden-brown, shaking the pan regularly. Remove from the heat and set aside to cool. Once cooled, chop roughly.

2. Cut three pieces of baking parchment, each large enough to line a baking tray. Using a pencil and an appropriately sized upturned plate or bowl, draw a 25cm/10in circle in the centre of two of the pieces of baking paper, and a 20cm/8in circle on the third.

3. Lightly grease three baking trays with a little oil and line with the pieces of baking paper, pencil-side down. You should be able to see the circles through the paper.

4. Preheat the oven to 150C/300F/Gas 2.

5. Whisk the egg whites in a large bowl until stiff peaks form when the whisk is removed. (The egg whites are ready when you can turn the bowl upside down without the eggs sliding out.)

6. Gradually add the sugar, one tablespoon at a time, whisking after each addition.

7. Whisk in the vanilla extract and cornflour until well combined. The meringue mixture should now be glossy and resemble shaving foam. Fold all but a few of the chopped hazelnuts into the meringue mixture.

8. Divide the meringue mixture among the three baking trays, spooning the mixture into the boundaries of the circles and spreading with a spatula to smooth. Set aside.

9. Reduce the oven temperature to 130C/270F/Gas ½ .

10. Bake the two larger meringues, one above the other, for 1½ hours, switching their positions halfway through cooking. (Reduce the oven temperature if the meringues start to brown too much.) Remove from the oven and set aside to cool. Cook the third meringue in the same way (if they can all fit into the oven at once, so much the better).

11. Once cool, carefully peel the paper from the bottom of each meringue.

12. For the filling, suspend a heatproof bowl over a pan of barely simmering water (do not allow the base of the bowl to touch the surface of the water). Add the chocolate pieces to the bowl and stir until melted. Allow to cool for a few minutes.

13. Meanwhile, whip the cream with the icing sugar until soft peaks form when the whisk is removed. Fold in the crème fraiche until well combined.

14. Transfer one of the large meringues to a serving plate or cake stand. Spoon over a third of the filling mixture. Using a dessert spoon, drizzle the meringue and filling with a little of the melted chocolate and sprinkle over one-third of the raspberries.

15. Top the first meringue with the second of the same size and repeat the filling process. Finally, add the smaller meringue to the tower and fill as before, drizzling over all of the remaining chocolate and sprinkling with the raspberries and reserved toasted hazelnuts. Dust with icing sugar and serve.