Whisk the egg whites in a clean, grease-free bowl until stiff. Add half the caster sugar and whisk again until mixture reaches the "firm peaks" stage.
Mix the ground hazelnuts together with the reminder of the caster sugar.
Fold this slowly and carefully into the meringue mixture, preferably with a metal spoon, until it is thoroughly mixed through.
Spoon the mixture between two 7 to 8 inch sandwich cake tins, lined with parchment paper, reaching up the sides of the tin, to ease getting it out when baked, and roughly "smooth" over to fill the tins, leaving the top uneven.
Bake in a moderate oven, on the centre shelf, for approximately 30 minutes, or until just firm to touch on the surface and nut brown.
Leave to cool in the baking tins and then turn out on to wire trays. Remove the parchment paper.
Cover the smooth side of one cake with whipped cream and fresh raspberries. Turn the other cake over so that the rougher, baked side is uppermost, slide on top of the cream, therefore "sandwiching" the two together and dust with sieved icing sugar. Keep in the fridge until ready to serve.
For a Raspberry Sauce, if you have a glut of raspberries, make a puree to serve as a sauce. Whizz the equivalent of 2 punnets in a blender together with the juice of half a lemon and 1heaped tablespoonful of caster sugar (or more if you prefer it sweeter).
Sieve through a fine mesh plastic sieve into a bowl, using the base of a ladle or a wooden spoon to push it through, to remove the pips. Store in the refrigerator and use within two days at the most, or freeze the raspberry sauce for later if you prefer.
