Mix the egg white with sugar and salt and add food starch gradually to form a mousse.
On 3 pieces baking paper place the egg mousse and bake in a preheated oven ( 150 degrees ).
Leave the meringue to cool when done.
For the filling
Mix egg yolks together with sugar, vanilla vial, food starch and cocoa. Blend well and boil with milk until thickened.
Allow to cool and meanwhile whip the sour cream.
When is half whipped add half a tablespoon of fat sour cream and continue until it is well whipped.
On a plate put a layer of meringue, a row of cream over it, walnuts as desired and continue with the same process until you finish all meringue layers.
Brush top and sides with remaining sour cream then pour the white frosting.
For the frosting:
Pour powdered sugar into a bowl, add lemon juice and vanilla.
Mix well until you get a creamy composition.
Beat egg whites separately into a mousse. Mix the mousse with the sugar composition.
Pour this icing over the cake and transfer everything to the fridge for a couple of hours.