For the yogurt cake base, beat the egg whites until stiff, add the sugar and continue beating. Fold in the grated nuts and place in a cake tin.
Bake at 160°C for about 45 minutes. Allow to cool.
For the filling, soak the gelatin according to package directions, dissolve in the lemon juice. Mix the yogurt with the sugar, stir in the dissolved gelatine and fold in the whipped cream.
Cover the yogurt cake with the filling.