butter, for the tin
225g hazelnuts (skin still on), toasted
6 eggs, separated
200g caster sugar
FOR THE TOPPING
350ml double cream, softly whipped
250g fresh raspberries or sliced hulled strawberries, or a mixture of the 2 a few mint leaves (optional)
icing sugar, for dusting
YOU WILL NEED
23cm/9in springform or loose-bottomed cake tin with a depth of 6cm/0.5in
Heat oven to 160C/140C fan/gas 3. Grease the sides of the cake tin and line the base with a disc of baking parchment. If you’re using a springform tin, make sure the base is upside down, so there’s no lip and the cake can slide off easily when cooked.
Put the toasted hazelnuts in a food processor and whizz for a few seconds or until they form a coarse powder with a few larger chunks for texture. Using a hand-held electric beater or an electric food mixer, whisk the egg yolks and sugar together for 5-7 mins or until pale, thick and mousse-like, and a trail of the whisk can be seen. Fold in the hazelnuts.
In a separate, clean bowl, and using cleaned electric beaters, whisk the egg whites until they form stiff peaks. Gently fold into the yolk mixture until incorporated. Tip the batter into the prepared tin and bake for about 45 mins or until a skewer inserted into the centre comes out clean, and the cake begins to come away slightly from the edges of the tin. Don’t worry if it dips slightly in the middle.
Remove from the oven and allow to cool in the tin for 10 mins. Loosen the sides using a small, sharp knife, then carefully remove the sides of the tin and leave the cake on a wire rack to cool completely before transferring to a serving plate.
Spoon the softly whipped cream all over the top of the cake, leaving a gap about 1cm wide around the edge, then scatter the raspberries or strawberries over the cream. Decorate with a few mint leaves, if using, then dust with icing sugar.